Hey, new guy here. I have a 93 pickup with 22re and manual 5 speed. I have a new issue that popped up, and I can't get it figured out because the truck isn't helping me with the diagnostics. While idling or driving my CEL will come on and go off, while driving when it's on I can feel the drop in power and when it goes off I can feel the truck immediately accelerate and regain power. Here's the part that's kinda strange, when sitting idling in neutral when the light comes on the RPMs raise, when it goes off they drop? I have tried many many times to jump TE1 and E1 to get the code to flash, but nothing... the CEL just stays solid. I know my jumper wire is getting a good connection, because while running when the CEL is off the RPMs will drop like they are supposed to, but if the CEL is on the jumper wire does nothing. Also since driving with the CEL on my mileage has suffered.

It has a new TPS on it, and I checked it with the 4crawler steps to make sure it's still is spec and it tested fine. My plug wires and plugs are also only a few month's old, as well as my O2 sensor. It has driven fine for months with these new parts so I don't really suspect them.

Can the igniter go bad intermittently, and cause this issue?

Thanks for any help y'all might have!

 

Check the gas cap it tight.

 

Welcome to YotaTech.

If you had a good E1-TE1 connection, you'd either get a 2-Hz steady flash ("no codes"), or the stored code. If you really have a good connection and a solid CEL, that is one of the very few times I would suspect an ECM problem.

Has nothing to do with the CEL on a '93.

You're thinking of a "modern" vehicle with an internal pump to pressurize the evap system to test it. The loose cap can throw an OBD-II code of P0455 or P0457.

 

A 93 is a modern vehicle compared to my 86. LOL.

 

Ok, today I went out and checked grounds based on my issue possibly being an ECM issue (I searched the forums for ECM issues and it suggested testing grounds). I checked all the grounds under the hood and they were good. That thread also said E1 is straight body ground, so jump the TE1 directly to a good known ground and if I get the CEL to flash then I have a ground issue somewhere, but if it stayed solid then it was probably the ECM. When I did the test to ground TE1 still no flash just a solid light!! I also probed between the battery positive and E1 and I got 12.5v so that shows the diagnostic plug seems to be ok. I hate throwing parts at a problem, especially $180 parts, but when the darn thing won't tell you what's wrong and signs point to it. It is what it is.

 

Just wanted to post an update. My problem was the ECM. I tried to purchase a refurbished one from a vendor (FS1) who said they actually didn't have one, but promptly issued me a refund. Then I tried to get a repair service (NEAT computers) on mine and they said they probably wouldn't be able to fix it depending on what's wrong with it because some chips are no longer manufactured. So I put a lookout on Ebay for when a used one would become available/listed and I bought it as soon as I got the notification. Now my truck runs great again!!

Thanks!

 

I'm having the exact same problem with my 93. How did you determine your problem was the ECM,? Thanks.

 

Because trying to get the check engine light to give me a code wouldn’t work. When jumping under the hood I couldn’t get the computer to flash the code of what was wrong. I talked to a local Japanese auto mechanic and he said yep, that’s a tell tell sign the computer is bad.

Even though my truck runs fine now I still keep an eye out for another computer on eBay for one at a decent price. People selling them now seem to think they are made of gold, wanting what I consider crazy prices.

 

Thank you so much for the response. I'm having the same problem with not showing a code. I've done the same things as you. Guess I'll look for a ECM, they are definitely expensive.