GDElpaso

When I jump the diagnostic terminals with a CEL on I do not pull any codes.

The timing also does not change when warmed up for a timing check.

I'm having some issues and need a starting point.

Robert m

iTrader: (2)

Check the TPS adjustment. Its been said on here that if the TPS isn't set correctly, the diagnostic port wont work right.

GDElpaso

How can TPS nullify jumped terminals?

pnwadv

Having similar issues. First thing tomorrow, checking the TPS to see if there are any issues going on there...

Robert m

iTrader: (2)

https://www.yotatech.com/forums/f116...ng-tps-279533/
https://www.yotatech.com/forums/f116...e-idle-233689/
"TPS diagnostic port not working site:yotatech.com" I put this into google and got those results but there are lots more if you want to read through them.

GDElpaso

Factory TPS tested bad, replaced with new. Followed TPS guide on 4crawler, idle quality improved.

However, the intermittent CEL remains, it only happens between 1500 and 2500 rpm. The sputtering still occurs at partial throttle between 2500 and 3200rpm. Jumping the terminals still does not change idle.

At this point I'm questioning the ignition system and possibly the vacuum operated systems. Fuel pressure might also be a consideration, however, it has a relatively new pump.

Terrys87

iTrader: (1)

On my experience with an intermittent check engine light, it has been a vacuum leak some where or a hose not routed correctly. I am betting that when your light comes on, and then you floor it, the light goes out, am I correct on that? That has what I experienced. Later on I would find some leaks, hoses dried out and cracked that needed replaced or something similar.

Also when I got the intermittent light, I could not pull any codes so for myself that nearly convinces me I have a leak somewhere and has worked up to this point for me.

GDElpaso

The light comes on at partial throttle. But I've eliminated the TPS as the culprit.
I may just delete the egr, and reed valve to get rid of a good number of vacuum lines.

scope103

Does the CEL flash continuously about 2x / second? If not, either you haven't successfully jumpered it, there is a problem with wiring to the diagnostic plug, or you have a much more serious problem with the ECM.

If it does, the ECM doesn't have codes. Some (few) intermittent codes are not stored.

GDElpaso

The CEL, doesn't flash, nor is there a timing change after warm up. There are still dead spots within partial throttle.
I've jumped te1 to e1 with no effect. I've had a mechanic suggest a grounding issue. I'll double check the plug to see if it has good connection.

scope103

Ground is easy to check; use your multimeter to check for continutity to ground from E1.

I don't know what voltage should be present on TE1, but there almost certainly has to be either 12v or 5v. If you get something close to 0v, I would suspect a wiring issue.

GDElpaso

No continuity...
Damn gremlins.

RJR

As scope says, also check the voltage on TE1. Not sure if it should be +12 or +5V, but your multimeter will tell you. If the voltage is good there, you can ground that pin anywhere to pull the codes - it doesn't necessarily have to be grounded to E1 if E1 happens to be open.

GDElpaso

Nothing happens. I'm gonna check the plug. After that it's following wiring diagrams.

GDElpaso

Diagnostic plug has solid connections. Ignition coil is within spec.
CEL solidified, still can't pull any codes

pnwadv

Can you post a picture of your jumpered port? Just so we can rule that out? I've heard some people post about using different metals will change things too, so maybe try a different jumper...

scope103

I'm not sure what "solidified" means.

When you have key-on, engine-off, does the CEL light continuously? If not, you might have something as simple as a burned-out bulb. That's not hard to check; the W pin in the diagnostic connector is the CEL; if you get 12v there with key-on, and pulsing 12v with TE1 jumpered to E1, then your problem is just the light.

BUT ... If you have no continuity to ground on E1, it doesn't matter how "solid" your connections are. Something is pretty wrong with your wiring; you need to trace it out with your multimeter until you find the disconnect or broken wire.

GDElpaso

When I said solidified, the light had gone from intermittent to constant ON.
I replaced my Frankenmeter with a 82 supra reman.
Today I deleted the EGR, and PAIR valves, rerouted and replaced vacuum lines, and added a support for the AFM to keep it more level and act as a possible ground. Cleared codes and got kicked out of the shop I was in (time ran out). Didn't get a chance to check continuity.

Wiring diagrams for E1, suggest it's the ground circuit for the fuel system grounding out at the AFM and the circuit open relay. The support is just some simple steel strapping with holes punched in it, it's fastened to the fender using existing threaded holes.

Went on a drive and the stumbling seems to be gone. Throttle response is good. But idle is still inconsistent, and there is still a noticeable surge around 3-3200 rpm.
At startup the engine will now occasionally just start and die unless it gets some throttle.

There is poor wiring near the plug for the distributor sensor, and I will test the coolant temp sensor. Hope it's not the knock sensor.