Intermittent Power Loss

[coronan]

Hello,

i have an 87. It looses power intermittently. For less than 1 second.
The check engine light flashes when it happens then goes off.

I had a code 11. Replaced TPS.

Power still cuts out and the CEL flashes. Its becoming more frequent.
No codes any more.
It happens in any throttle position. AC is off.

Ideas???

[timsrv]

Can't say for sure, but sounds like an ECU issue. Any time the CEL light flashes there should be a code stored. If no code that would make me suspect the ECU. If you have an extra one or have access to a cheap one I'd swap it out and see what happens. I had a similar issue on my 86. It would hesitate and I'd get the o2 code. I changed the o2 sensor and reset the ECU. Next day it still hesitated and after driving about 20 miles the CEL started blinking again. When I got home I checked codes. Sure enough, o2 code again. So I checked continuity between the o2 sensor and the ECU & it was good. So I changed the ECU and hesitation was gone. No more codes either. Performance and mileage also improved.

Up until about 3 years ago I'd never seen a bad Toyota Van ECU. Since then I've seen 3 of them. I guess age catches up with everything sooner or later. If your timing is right you can find cheap ones on eBay. Just shop by searching for the same part number (printed on your old one). I like to keep at least 1 spare for every van I own. On average I've paid $20 - $50 each. Tim

[coronan]

Thanks Tim!

So far 120 miles and no more issues.
I was thinking ECU in the back of my head but thought it unlikely.
Now to shop for another Backup. Or MegaSquirt.

[timsrv]

Yeah, the 1st bad ECU I encountered I refused to believe it. I drove for 3 months with the issue. Eventually process of elimination left nothing else. Sure enough, bad ECU. Now when troubleshooting I consider it just as likely as anything else. Even more so when there's hesitation involved. The one I'm running now was $20 off eBay and looked so bad I was hesitant to install it. Looks can be deceiving though as the bad one looked pristine. Van runs awesome with the ugly one. Tim

[ViennaSausage]

Hi guys. I recently started having the same trouble on my 1987 4WD automatic; slight hesitation at higher rpms, CEL flicks on briefly, then all back to normal. After reading a few of the threads here, I thought I would check out and replace the ECU. From pictures I found, it looks like it is located in the driver side panel, correct? I just tried to pull of the paneling and only saw the housing for the seatbelt. It didn't look like there was anything else there. Granted I can only partially visualize behind the panel because I cannot remove the stripped bolt on the engine access strap.
Am I looking in the right place? Thanks in advance for the help.

[timsrv]

Yes, you're in the right place. The engine cover strap and the panel behind it need to be removed. Then the seat belt assembly (roller) will need to be removed along with the plastic liner behind it. When all that is out of the way you will see where the wire harness hooks up. Take all the wires off then there's a 10 mm nut and 2 phillips head screws that attach the ECU to the pillar. It's not immediately obvious that these are the ECU fasteners, just take them out of the pillar and the ECU will be loose. It will then drop down out through the seat belt spool hole. Tim

[JDM VANMAN]

Tim,

are all the ECU's ranging from 86'-89' interchangeable regardless of automatic or manual transmission and 2WD OR 4WD? Or are they based off of specific VIN # significance?


thank you.:thmbup:

[timsrv]

There are exceptions, but typically 84 - 85 are the same, then 86 - 87, then 88 - 89 (don't ever intermix between these year ranges). There are other differences inside these ranges (especially 88 - 89) for California spec emissions and/or auto vs manual transmission. Due to this, I do not recommend buying another unit until your old unit is removed and you document the part number (imprinted right on the ECU). Then I'd suggest using that part number to do a search on eBay. I have a minimum of 2 good extra ECU's for all my vans as I will eventually need them. If you wait until one fails, then you will likely pay a lot more (out of desperation). The most I paid was $50 for a CA specific 89 ECU. Most of the rest I paid between $10 - $20.

With used parts you never really know if they are good or bad (especially electronic ones). This is why I test these (and other things) before I need them. When I get these type parts, I install them into a good running van & leave them in for at least 2 weeks (some "tests" may last for months or years). At some point I rotate and the known good parts get put on the shelf (bad get thrown away). Fortunately I've been pretty lucky with eBay and salvage yards. With anything this old, I highly recommend you have at least one known good extra ECU, igniter, distributor, and Air Flow Meter (AFM). Coils and ECU temp sensors are also a good idea to have, but those are still inexpensive and easy to find at parts stores. Normal troubleshooting doesn't always result in a "smoking gun", so sometimes there's just no better way to prove a problem then to replace a part and see what happens. It sucks when those parts cost $500 each (especially if you're not sure they're bad), so save yourself a future headache and stock-up on these things when you don't need them, then you can usually purchase for cheap. Ebay has a "saved search" feature that will notify you when a searched for item is listed or becomes available. Tim

[JDM VANMAN]

Thanks Tim,

I'm looking to pickup a couple spares as well, is there another name the ECU is called? I was looking at Picknpull's pricing catalog but they don't have a listing for the ECU's. The only name that I was thinking is Electronic Engine Control Module? I've seen that for $100 at another wrecking yard site.

[timsrv]

Yes, ECM or ECU. I've never gotten one from a salvage yard as they think they're made of gold ($100 - $150 is the norm). I've had my eBay ones for years now & haven't purchased any in some time, but I suspect they still occasionally pop-up for cheap. Just save an eBay search and have them notify you whenever that part number shows up. Tim

[ViennaSausage]

Thanks Tim. I found it. Could not unscrew the engine strap, it's been totally stripped; mostly by the PO, but I made it worse.
The ECU number is 89661-28060. Ordered one off ebay for $75 bucks. I hope it does the trick. I'll let you know after I install.

[ViennaSausage]

Issue resolved! I hooked up the replacement ECU yesterday and after a short drive then, and commuting today, the engine was running smoothly; no hesitation, no check engine light. Thanks again for the help.

[timsrv]

:dance2::dance1::dance1::dance1::dance2:

[trestlehed]

There are exceptions, but typically 84 - 85 are the same, then 86 - 87, then 88 - 89 (don't ever intermix between these year ranges). There are other differences inside these ranges (especially 88 - 89) for California spec emissions and/or auto vs manual transmission. Due to this, I do not recommend buying another unit until your old unit is removed and you document the part number (imprinted right on the ECU). Then I'd suggest using that part number to do a search on eBay. I have a minimum of 2 good extra ECU's for all my vans as I will eventually need them. If you wait until one fails, then you will likely pay a lot more (out of desperation). The most I paid was $50 for a CA specific 89 ECU. Most of the rest I paid between $10 - $20.

Question about the ECU part #: For my 1987 4wd Automatic I have read that for California Vans the specific part# is 89661 - 28090.
If I open up the driver's side pillar hatch behind the seat belt assembly, is the ECU part# easily visible or do I have to get in there and remove the whole thing?

Thanks.

[timsrv]

I can't remember for sure, but I think you need to remove it to see the tag. Sorry, but it's been a long time since I've had to pull one. Tim

[JDM VANMAN]

I believe it’s completely hidden behind the pillar, you’ll need to

1)remove the connector harness
2)remove the 4 bolts that attaches it to the pillar
3)slide it down and out

Its been a couple years since I’ve pulled one. I saw some refurbished ones on eBay for about $350:dizzy:

JDM

[trestlehed]

Ok, thanks for the replies and info there Tim and JDM.:)

[reclusebrown]

Hey guys I've been having similar issues with my 1986 auto since I had it. For the most part the only problem was a intermittent power issue when I accelerated so I got another ECU and it seemed to be corrected. But Last weekend when I drove her I lost all power in the middle of the road and couldn't crank back up, (no spark). Thinking quick I removed the old ECU and replaced it back with the original one and it started up, but when returning home it died again,( battery has a full charge). Im thinking there might be a issue with the connector wires going into the ECU since the van reacts differently whenever I move them around.
Is there any wire/pin I should investigate that would cause my van to lose power while driving? All suggestions are appreciated

[bikeregg]

Could be a bad ground. Check ground connections for the ECU, alternator, under the dash and the battery.

[reclusebrown]

That's the first thing I addressed. I sanded all my grounds
Thanks