-found the o2 sensor wire, changed thread to different problem...

Alright guys, so am in the process of performing a CA legal 22r to 22re swap on my LCE stage 2 stroker engine. I have got the truck running, I'd does have a slight stumble when the revs are held around 2k. My problem is that I have no way of seeing what codes I have because I have no check engine light...

The light does not turn on when the key is on, I can jump the diagnostic box and nothing happens, other than my idle lowers. I have Ohm the purple wire at the ecu to the cluster and no problems. The weird thing is that the engine light would come on for the first few times I started the truck but then stopped... I have checked every fuse and found no problems, as well as grounds...

I will check power to the engine light wire in a few minutes, but I'm thinking the ecu may be bad? If I unplug the knock sensor the truck does not throw a cel nor does it change in the roughness of the motor..

There is a bulb in the cel holder, bulb is good, no power to the bulb.

Let me know what you all think, thanks!

 

Okay so I checked voltage at the purple wire going to the cluster, it had .57v at cluster and .57v at the ecu pinout.

On the back of the cluster at the contact patch I have 12v. But I can't find the ground for the bulb. So maybe the ground for the bulb is bad? As in a bad cluster? Switched bulbs all around with no luck. At this point I'm stumped.

 

Sounds like something is being shorted in the cluster. The violet wire is actually the return path for the light so if your getting power after the light something is defiantly wrong.

BTW if you want to temporary check the codes grab a 12v light, grab scrap wire and put it on your positive battery terminal. Hook the light up to the wire, then get the violet wire on the return path for the light. Put your key to "On" and short out E1-T1 in the diagnostic box and enjoy!

 

You sir are amazing!
I performed the temp engine light with one of my rock lights. Here are the codes that popped up...

21- oxygen sensor signal
22- water temp sensor signal
24- intake air temp sensor signal
31- manifold air flow sensor signal
41- Throttle position sensor signal

All of those are open/ short to ground...

I adjusted the tps, it's is spot on. Ohm the afm ohm is spot on. New efi coolant temp sensor....

It runs right now, but has a studder throughout the rpm range and pops out of exhaust after the rev... Think it's a bad ecu?

 

After you touched any of those listed like ..adjusted the tps and put in a coolant temp sensor did you restart the ecu and see if the codes come back?

If you haven't adjusted the timing then I'm assuming it's running lean and when these trucks run past 5 degrees timing the vehicle will hesitate I have found.

Thats quite the list of codes too.. most of the time ECU's don't crap out unless they go underwater hahah. If you have access to another ecu it doesn't hurt to try, aslong as its the later ECU.

 

I have had the ecu unplugged for a few minutes and had the batteries off for a while too. But I will pull batteries off for a few hrs and efi relay too. Hopefully that will fully reset the computer and we can start fresh...

I have the timing set right at 5* with the terminals jumped. I will recheck tomorrow also... I noticed that the truck doesn't have the power it had when compared to my weber 38.. but there are obviously gremlins to figure out...

 

Pulling the engine fuse in the driver's side kick panel for about a minute resets the ECU too.

I have seen a few 22re's that stumble in neutral when trying to hold rpms over 2000, some people claim that retarding the timing 2-3 degrees fixes that.

Is your ECU the same year as the other electrical parts? Because if you use the later year ecu in a early gen efi you will get mostly all the codes you got, ask me how I know that

From the sounds of this the ECU is suspect since your getting lots of errors on the check engine, but you have tested them to be working.

 

Yes everything SHOUOD be from the same vehicle 1987 year... I will try resetting them, and run the truck for a bit and see what happends... I'm hoping it is the ecu as that would help a lot lol.. what are some ways that I should check each wire for shorts. Ohm the wire at the sensors then at the ecu pinout? What are some ways to see if the ecu is bad? Unfortunately I don't have an extra anywhere near me.

Thanks again for the help!

 

Yeah checking for shorts the way you listed would be the best I think, try wiggling the wires to and seeing if it makes a difference. Not totally sure on how to check if the ECU is bad or not.

If you got a pick n pull near you that would be your best bet for one.

No worries, I got some wiring gremlins in my recent 22r to 22re swap to and its quite frustrating! When my efi was working perfectly it was a noticeable difference from carbed.

 

Okay got some new feedback for ya guys!

Cleared codes and proceeded to get code 21, o2 sensor. Got a new denso single wire o2 sensor and installed. Right away get the same code.. Ohm the wire from the ecu to the sensor, all is good. Start truck and heat it up, get .06v at idle and .70v when revved up some, at the o2 and ecu pin...

Weird part is that it throws a code with the key on engine off, aftwr I just cleared it. Before i started it...

I do have a header ok the truck, o2 plugs into 3/4 cylinder 3 inches or so from the head...

Rest of the codes are gone. Truck still runs poopy... I'm at another bump in the road.

Thanks!!

 

Try taking a peak at the egr and see if it's clogged or stuck open. Or stick a piece of cardboard the same size as the gasket for the egr where it meats the intake and see if blocking it off helps the problem at all.

Open up your ECU and check if you can see any burn marks or anything broken that may indicate your ECU is toast.

 

Thanks for the help your an awesome guy!

I put a thin piece of metal on the egr port on the intake manifold and bolted egr back on. Truck didn't make any bit of difference. So I think that is ruled out??

I will pull the ecu right now and open it up to see what I find! I'll report back in a few!

 

Well pulled the ecu apart. Unfortunately I did not find any burn marks, cracks, damage inside the ecu... I cleared the codes, and turned the ignition on with the terminals jumped. Sure enough code 21 appears appears... didn't even start the truck.

I originally couldn't find the o2 sensor wire. After following the big gray wire from the ecu I found it going to a rectangle plug right next to the inside fuse panel. So I removed the gray wire from the plug spliced into to an extra o2 plug I had. And yes I spliced the black to black and the shielded to the shielded... Ohm it and everything checked out good. Just figured I had to put that out there.

Could the ecu be from an 88? That maybe why it shows code 21, HEATED o2 sensor short? When my 87 is only a single wire o2? That might explain the wiring harness on why there wasn't an o2 plug on the driverside loom, but on the floor board next to the internal fuse block?

 

My 86 one wire O2 plug comes right by the igniter so it sounds like that's a heated sensor harness. 88 ECU is different from a 87 because the change in injectors and all that extra wiring. Weird how your o2 is only a few inches from the motor when heated plugs should be farther down.

Will not having the heated o2 portion hooked up affect performance I don't know

Sounds like you got some mismatched parts if you got a heated o2 sensor harness, newer ECU, but then older style exhaust manifold

 

I'm using my header from the 22r, which has the o2 port on it... this sucks because I need to make this truck as legit as possible for my year 1987 in order to smog it and get it refereed as an 1987 22re... what are some distinguishable differences on an 88 22re when compared to an 1987?

 

Don't think anything visual besides the o2 I think was further down. Probably could still pass as an 87.

I'm assuming you don't have a heated o2 around to try and plug in and see if it makes a difference.

 

Well I do in fact have an 88 harness. My injectors are those of an 88... so is the o2 plug I found.... looks like I'll be going to find a 4wire o2 and making my own wiring harness. Problem is, on the 88 aren't the o2 downstream? Could I leave it on the exh mani

 

Probably could get away with having the heated o2 up there for smog then move it down stream later

 

Well went to the junk yard and got a heated o2. Re-spliced that into the harness.

And..... the check engine light went away. Now I have ZERO...

Weird part is the truck still runs a little rough, doesn't have the power it should, I feel... and when coming to a stop or slow cruise, the rpms go up and down, a few times... idle screw is 1.5turns out, timing at 5*, new gaskets, new vacuum lines, etc... maybe the tps has a flat spot or is wacking out??

Now I get to see how screwed I'll be to ref my truck... oh and the heated o2 is still in the exh mani.

 

Haha well atleast no check engine light!

Take a volt meter to the tps and see if the volts climb/drop smoothly with the throttle

Now did you replace the vacuum line going to your brake booster? If its got a vacuum leak that would cause some issues with rpms when braking. Also does the truck rpms go up and down when pressing the brake?

Now what's your timing at without the diagnostic box jumpered? Should be 12ish degrees. If it's still at 5 degrees you could have an ignition problem.