SOLVED: Camry CSI 4cyl 1996 ECU injector problem

[trentmeyer23]

As you, Trent, commented in your first response. "The system is so simple its laughable" Well after three weeks of trying to get it fixed I regret to report. I do not find anything laughable about the situation.

There is clearly an external issue that is causing the same fault with a replaced component. Throwing parts at it, is not going to fix the problem.

[Jim.]

Thanks for your decision to continue communicating with us. Also, the details of suppliers etc. above could be useful sometime in the future.

I'm a bit puzzled by this part of your installation instructions:

.................................

The mechanic at the wreckers strongly recommended not using the original cabling (yellow and white wire) but to cut them close to the plug and patch in at the cut wire and run a separate pair. He said the ECU came off a fully operational engine and therefore taking this precaution it should work. eliminating any intermittent shorts in the harness.

The unused wire ends should be heat shrinked to prevent shorting anything at either end and tied back with a cable tie.

......................................................

What cabling is this? My ECU is simply plugged in with a couple of large multi-cable couplers. No cutting of wires necessary to change it.

I agree with what Trent has said however. After all, the exact same fault developed with both the original ECU and the second one that replaced it. The fault is clearly external to the ECU.

It's good though that you have the necessary skill and experience to repair your damaged ECU; this might save you a lot of money. What you have written about it reveals a couple of potential problems that older units might develop and how to fault find them and fix them. I'll cut and paste your report for future possible reference.

Jim.

Edited March 11, 2015 by Jim.

[OldMech]

Forgve me if this is out of order Sometimes a very different tack to a subject is helpful.

Also after being involved in the TV service field since '58, TETIA member and State president, it was very troublesome at the end to discover that imitation solid state devices were on the market through normallly reliable channels. If their price is low where are they made?

This discussion may put in mind another train of thought, if permitted.:http://www.toymods.org.au/forums/threads/7956-No-injector-pulse-why

[Sploddy]

Ok. latest comments read and noted. I feel a summary of the relevant facts is probably due at this point and bit of clarification.

1. When this problem occurred, my personal knowledge of the Camry electrical system was zero apart from the basic elements. I had had no previous experience of EFI cars other than carby engines going back to a 1936 Wolseley Hornet with Twin Webber downdrafts to the TA22 Celica (1972). Though I have over 60 years experience in other electronic industries.

2. I entrusted a qualified mechanic and auto electrician to diagnose and fix the problem described as "Failure of ECU to provide injector pulsed voltage to 1 and 3" and was heavily charged for a replacemnt 2nd hand ECU, which failed within 30 minutes of our resumed journey. Because we were "in country" 300 kms south of Perth (home) it was necessary to put our camper on a camp site and wait for a week before getting the car back.

3. In my concern I decided to ask questions, and found TOC and posted my problem in the hope someone had previously experienced the same issue.

4, Since 21st February, the repairs at the Service Centre have been ineffective and no solution found as to why, nor was any prognosis forthcoming

5. Therefore on 10th March I took steps to bring to car back to Perth by my eldest son. I have also purchased a working ECU and obtained circuit diagrams of the ignition system outside of the ECO

I am unable to locate a diagram of the actual ECO only a block diagram. However with my electronic knowledge in other fields I have been able to identify the circuit path relating to the Pulsed source for the injectors, (described above) and I have placed an order for a number of components which will allow me to repair the faulty ECU which is well within my skills and capabilities.

6. I will after getting the car back do a complete analyses of everything related to the ignition and fuel circuitry. I will not connect the working ECU I bought, but use the old ECU I have repaired.

taking precautions against blowing the repaired ECU and monitoring its function at various points (see Part II Comments below).

7. If the car starts and runs efficiently enough for me to get the car to a qualified Auto Electrian who has a full Toyota Electronic diagnostic analyser. I will place it in his hands to confirm whether or not there are any other problems.

8. I now anticipate in receiving the car back on 21st March and the transistors and IC 101 (The transistors, I have ordered multiple quantities they are very cheap) will arrive during the following week.

Part II Comments.

1. I think it has been well established that there is a cause outside of the ECU that has created the identical fault. That the fault does not show up on basic tests indicates that it can be one of several things, heat related, corrosion, or an intermittent mechanical issue. in electronics heat can play a big part in the the expansion or contraction of metal, as screw or connector that is not firmly engaged or even corroded can stop a circuit from working. Another thing is electrolysis, I think most people are familiar with old wired that has been in use for a number of years can turn the copper black, to point of losing connectivity in QC joiners,terminals and crimped plug and socket pins. Jim commented on the wrecker mech comments about bypassing the ECU wiring to the injectors. yes the connector which has the white and yellow is a multipole plug and socket module containing three separate multi connectors a 6way a 16way and a 4way designated connectors.

The 6way has 5 wire ports & uses the upper three wires which are white/black white and yellow. the lower white/black blank blank. The 16way and the 4way have a total of 16 wires.

The wires can only be removed by a special pin extractor as the pins have a small tag that locks them into the housing. I do not have an extractor. I will see if I can borrow or buy one.

To bypass the original injector wiring in the harness as the mech suggested, is to either remove the wire by taking out the pins or cutting the wires (white and Yellow) and joinning a new separate pair to the injectors in case there is an intermittent fault in either wire.. Ideally it would best to remove the pins, the mech gave me a set of the three plugs with 150mm wire tails as spare housing or for pin recovery if I managed to find a removal tool ( hope that clears that up Jim) when refering to wire colours multi coloured wires are written down as 'body' 'stripe' and can be either "white black" or "WB" a single colour is obvious.

2. Testing and monitoring. In electronics there are included on circuit boards are a number of test points (TP) where an expected voltage/current is shown. It has been my practice in the past when testing a repaired unit to monitor these points and to take precautions against unforeseen external faults. Thus I will be monitoring with individual meters voltage and current in the wires to the injectors from the ECU. a temporary inline fuse which will blow before the component parameters are exceeded (ie short) will protect the system under test. I do not use throw way fuse links for this purpose but a test fuse block that takes the desired fuse wire rating. Much cheaper and immediate visual effect.

3. Thanks Laurie for the link, yes, frustrating and yet again nothing was really resolved and the feed fizzled out. But an interesting read :)

Thanks Jim also for encouragement.

There is too much waste in the automotive industry, where a single blown component results in an entire control system board being thrown in the bin because many of today's mechanics are only "Plug and Play" techs or they do not have the knowledge to trace and fault find in actual electronic circuits, preferring to replace various "black boxes". In many cases the repair component is as cheap as $1. To me I would rather spend a few dollars and get a device working, It can be challenging, but when you switch the device on again and it works it gives you a sense of achievement. Having a spare test ECU has advantages of not blowing a known good replacement unit.

However, if you do not understand Ohms Law and have the correct tools or knowledge. I do not recommend carrying out repairs on equipment using highly sensitive CMOS devices. It can not only be dangerous but ignition systems create very high voltages.

One thing is for sure, I have learned a great deal since my first post and have read an enormous amount of information and received external comments from EBay sellers to Mechanics. One Ebayer commented after advising me an ECU he had was not suitable for my car, "That the early Camrys were notorious for ECU problems". How true that is I don't know, I have only had this one for a little under a year. basically its a nice car, until now it has run sweetly and started with out fail at the touch of the key in both hot and cold weather. I am quite happy to spend some money on it to maintain it in a roadworthy condition. It looks good cosmetically, with a few minor blemishes which a spot of car detailing can eaily eliminate.

I am going to sit back and try to uinwind over the next week as nothing further can be done other than assemble my test equipment, when I get the car back and the old ECU fixed I will bring this up to date. Maybe a nice "Merlot" this weekend will go down well.

Watch this space.

(all errors and typos are mine)

Edited March 12, 2015 by Sploddy

[Sploddy]

Addendum

I have been going through the Haynes manual of the Camry (which covers various models including the V6) and having not read it completely, I came across the chapter on ECU self diagnostics. By shorting out the pins E1 and TE1 on the ECU diagnostic block and observing the internal display panel with the ignition switched on an indicator will give various flashing codes indicating faults found by the ECU under differing engine conditions. it also shows how to read the codes and list some 21 codes and what they mean and possible fault location.

The diagnostic data should be erased after the faults have been read and rectified by removing the shorting link and the 15A EFI fuse, then replacing the fuse.

This and other detailed information on testing is also contained in other chapters.

Because of the large number of pages and copyright laws. © 1997. I do not propose to repeat it here. However I recommend that anyone interested should obtain a copy of the Haynes Repair Manual for the 1993 to 1996 Camry/Vienta and Holden Appollo cars.

ISBN is 1 56392 257 6 which can be purchased on line or from most Auto stores in Australia..

[OldMech]

Excellent. I have the manual and am pleased that is has that section. A
snag is that any such diagnosis is normally carried out with the system
in a 'steady state' condition. But it has to be of help. Good luck.
'Persistance is 99% of success' - as you would well know..

[trentmeyer23]

You can also purchase old factory service manuals on eBay and other such book selling websites.

[Hiro]

Toyota Special Service Tool SST-058 OBD1 Code Scanner

[Jim.]

Thanks for that comprehensive report Sploddy.

Yes, you have clarified the yellow and black wire question well enough.

While driving around town today in my car, I had a bit of an epiphany. If either injector #1 or #3 has a partial or intermittent short circuit, that would cause the output transistors driving them to fail.

I'm assuming the injectors consist of kind of solenoid device, with a coil and armature etc. If the coil is shorting between turns, this would cause a low impedance and could create the problem.

A couple of injectors second hand would probably be cheap. I would either have them checked thoroughly, or simply replace them and try it out.

As for the wires referred to above, if the wiring was visually inspected and found to be in good order as you report, I doubt if there could be any other problem with them. After all, one of them would have to short to chassis (earth) to blow the output transistors.

Jim.

Edited March 12, 2015 by Jim.

[OldMech]

The output transistors would need to have the short on their output/load side to blow most likely. As has been said, the injector coils. I've been trying to work out a link between the original mechanic's thorough going over in the first place and the resultant trouble. I'm rather against that technique. Preventative maintenance I suppose. But for me - 'If it's not broken don't fix it.' I've not been let down yet. Virtually four times around the globe. Like Albert Speer's walk in Spandau, muliplied.

A cheek! :http://members.virtualtourist.com/m/m/5c3d8/

Edited March 12, 2015 by OldMech

[trentmeyer23]

I think Jim could very well be somewhere near the money with the injector idea.

[Sploddy]

Hope this works. Copy of the 5SFE 4i circuit diagram and ECU connections 2 pages

http://dsmithdale.net/camrydocs/ecu1.oxps

http://dsmithdale.net/camrydocs/ecu2.oxps

The injector pulse output pins on the ECU are marked #10 and #20 white and Yellow

If using Firefox you should be able to click and view or download. Files about 2mb each

N-Joy :)

PS. Removing pins/wire from harness plug on ECU. On the edges of the plugs on the wire side are small hinged tabs. Carefully raise them upwards from the wire side and hold the wire close to the pin with a pair of small smooth flat pliers and gently lift upwards. The pins have small "pip" that lightly locks it into the shell, then locked in with the hinged tab. Do not use excessive force as you could pull the wire out of the crimped pin. If it does that, it was a bad crimp in the first place!

If you need to remove the wire, carefully cut it inside the sleeve crimp tabs, do not try to open the actual crimp, you will wreck the pin. Put the new wire thru the sleeve tabs with about 4mm of bared wire and solder to the top of the crimped area, there is room if you are neat and do not use excess solder.

The pins should have gold plated tips, clean with a contact cleaner do not use abrasives which will remove the plating.

Proprietory Contact Cleaning solvent is ideal for plugs and sockets. It washes and removes harmful contamination and dries clean. Always allow 20 minutes after using it before applying power, but use it sparingly in the first place, there is no need the flood the connectors.

Edited March 14, 2015 by Sploddy

[Jim.]

Ok Dave, it is very punctilious of you to post all the above details for the reader. That is all good reference stuff, however we are not the ones experiencing the problem.

I still don't know why you seem to want to interfere with the wiring harness and ECU connectors. If there is no visible damage to insulation, I don't see a reason to replace the wiring runs. Maybe I have missed something here?

Did you read my post # 34?

Jim.

[Sploddy]

No Jim, nothing missing :) I now believe that it has to be an injector breaking down. However I noted your comments and will check every possible avenue.

I posted that info ablout the connectors purely out of interest. As I have commented a wiring fault is possible so it remains on the check list.

ATM there is nothing I can do until I get the car back.

Dave

[Jim.]

".................................................

......................................... I've been trying to work out a link between the original mechanic's thorough going over in the first place and the resultant trouble."

Based upon what evidence? For all we know from the report, this mechanic did what was asked of him and did a full service of the car.

I'm rather against that technique. Preventative maintenance I suppose. ................ 'If it's not broken don't fix it.' I've not been let down yet........................................

If we all followed this logic, cars, trucks and planes would be driven and flown until a fault developed.

I would rather the airliner or glider that I'm flying in, or the car that I'm driving in this case, to checked over thoroughly periodically. Besides, the original servicing mechanic did not "fix" anything that did not need fixing.

I've been thinking about this since you posted it, and could not let it go without some comment.

Edited March 20, 2015 by Jim.

[Sploddy]

I agree with you Jim. Aircraft of course have scheduled "life spans" of components and are changed at designated intervals. All aircraft flying are not the same aircraft that were originally "in air" righ down to fuselarge panels etc. That is why properly maintained aircraft can fly the number of hours they do.

It would be nice to do this with cars, but it is just not economical for the average car buyer.. Those that have buy a new car each year and the peasant buyers their cast-offs. (A new car at today's prices would use up two years aged pension) However I think probably my driving days are coming to their "Use by date" and I will have to rely on Public Transport in next few years.

Today is collection day, and we do a 600Km rounmd trip together with my son and his 4WD and car trailer and bring the Camry back to Perth.

Yesterday I had interesting talk with the Manager of an Auto Electrician, whom I have used before. They have well fitted workshops, with all the good oil as far as diagnostic equipment etc and are respected in the industry. He posed a question after hearing my information,: "Have you actually tested the ECU yourself and is the output transistor to the white line actually blown?"

I was as we all known I have have not had physical access to the car since this problen occurred, he was suggesting that it is possible the mechs are looking too much at the obvious and the transistors are not blown, but the fault lies at other inputs to the ECU which can effect its operation, ie: sensors and other associated feed back in the ignition and fuel system. He said he has not experienced this actual condition, nor has he had problems with "intermittent" injectors, they either work or they don't. The major problem with injectors is lack of maintenance, cleaning etc. - however these faults are often progressive, with rough running and difficult starting.

So some food for thought. As previously mentioned I will thoroughly check the system and if the ECU does have a blown transistor I will replace it and take the car to the Auito Electrician and they will do a complete diagnostic test.

The Parts should arrive from "UTSource" in HK some time next week.

Watch this space. :) !!

[Sploddy]

Phase II diagnotics and repair.

Yesterday Saturday 21 Mar. We recovered the car after a 9 hour round trip. Everything went very smoothly and it helped that although only running on 2 cylinders we were able to drive the car onto and off the transporter and into the car port.

I also recovered the original ECU and last night removed the faulty transistor a 2SD2162 CMOS darlington power transistor.

The transistor was open circuit between Base and Emitter. When I receive the replacement transistor ($1.50 ea) next week will replace it and carry out further tests.

The power transistor also has a protection diode built in between the collector and emitter which also appears to be open circuit.

Current control resistors between the collector and ECU 12v power source will also be checked for continuity and voltage. The two output transistors are independently supplied from the main ECU 12V voltage source via series resistors and decoupling capacitors.

[Jim.]

Ok, good you have the car back home Dave.

Thanks for the update. I check the thread each day.

[Sploddy]

Sunday 22nd. Raided the replacement ECU whiich failed for the good transistor left and fitted into the original ECU. Installed in the car and she started first turn of the key running on all 4. Decided to check the connectors on the injectors, the injectors and connectors where covered in a fairly thick coating of grease and dirt, not the best for electrical connectors. I had problems getting three of them off they were jammed in tight. The are not easy to get at in the first place. Cleaned the shells and injectors and surrounding area with decreasing fluid and washed it off and left the car open for them to dry after removing any moisture with home made super long cotton buds on a satay stick.

Just taken it for a drive around the block and seems to be running OK It appears to be OK to get it to the Auto Electricians during the week. I may wait until I receive the spare parts so I can repair the other failed unit.

The second hand one I bought, although it is marked 5S-FE (it also has additional 'ECT' under the 5S-FE in smaller print). I will have to return or exchange that unit as it has different plugs and pinouts.

My original is 89661-33261 Sockets 26P 16P 12P Whereas the one I picked up is 89661-33660 and the Socket pins are 26p 16p 22p.

Why did it happen? I still do not know, I have checked the harness for shorts and injectors for shorts or abnormal resistance.

.

Also on connector one, the Yellow and White wires are on different pinouts. (Probably a later model, also the CPU is different)

Edited March 22, 2015 by Sploddy

[Jim.]

What was the resistance reading of each of the injectors?

[Sploddy]

What was the resistance reading of each of the injectors?

All reading very close to around 12 ohms with the harness disconnected at the injectors..

[Jim.]

Good, that is within specification as far as my information goes.

It seems there are low impedance injectors (around 3 - 4 ohms) and high ones, in the range of your 12 ohm.

So the search for the original fault goes on..............

[Sploddy]

This morning, the car started normally, just slight touch of the key and burst into life:) As Jim says, the search continues for why two different units went with identical faults. The first transistor shgowedd no physical signs of blowing, however the replacement on, had a large piece of the moulding blown out, that was probably what my son smelled, commenting on an electrical type burn. (I have no olfactory nerves - cannot smell anything).

This morning we did a round trip of about 10K to a hardware store and picked up load of shelving for our kitchen. The car drove beautifully like nothing every happened. I have left the glove box and moulding out ATM until I get the back-up transistors and repair the other unit. Then will have the Auto Elec check it out and make sure its programming has not been compromised. (Though everything appears to be functioning OK)

This will probably be at least a week, so unless anything drastic occurs will make my next post in a weeks time.

[Jim.]

Do you know how to check the computer codes yourself?

You don't need a code reader for this model. Simply jump two leads with a paper clip or wire in the analysing socket under the bonnet and count the engine light flashes after you turn on the ignition.

Full instructions and codes can be found in the manual. Do you have access to one?

[Sploddy]

I have the workshop manual now. Its also mentioned further back in this feed. Tks.