Hello everyone, I am getting my a$$ kicked by my 88 4Runner. I cant get the ground pulse to my injectors. I have read through every thread on here I can find related to this issue, and still nothing. Let me walk you through what I have and what I have tried.

88 4 Runner with the 22RE It started and ran when I bought it, sort of, but I was able to drive it up my driveway. I had to take the engine apart as #2 cylinder had no compression. hence the sort of.. It had bent valves on it, so I took it to the machine shop to get it fixed. Obviously while I had it apart I did a timing chain replacement, the whole nine yards. Yes, I know my timing is on point, I have even taken it back apart enough to verify through my troubleshooting.

Back to the situation, When I put it back together, I no longer have ground pulse to my injectors to get them to spray. I checked all the normal stuff, voltage at the injectors, checked my grounds from the ECU to the lug on the intake plenum. I am an electronics technician by trade, so checking wiring is kinda my go to thing.

Yes, I have spark and compression. I verified my TPS, Verified my injector resister, Verified my MAF Yes, it will run for a few seconds on starter fluid. I checked my wiring from the injector to the ECU, ECU to ground, and have been using my noid light, nothing. Checked the EFI relay, and even though it was good, I threw a spare in anyway. I have great fuel pressure.

Now I started to go way beyond, When I bought the truck, it came with bins full of spare parts that he collected over the years as parts became difficult to find. So I changed out the injector resister, nothing, I changed out the igniter, nothing, new distributor, nothing, second and third ECU, nothing.. Had the guy come by with his currently running '88, and we dropped parts in off that one with parts we know work, still nothing.

Like I said, the truck ran when I drove it up the driveway to fix it, but now I have nothing.

Any thoughts?

 

Have you got the intake piping completely installed??

 

I currently have the intake piping off in preparation to set the timing.

 

It will not run with the piping disconnected because there is no intake draft to open the Vane Airflow Meter.

Try piping everything up tight and attempt to start it.

 

I will try that tomorrow... Once it is started, can I remove the piping the verify the timing without causing issues?

 

NO. The engine will cease to run.

Why do you need to remove any intake piping to time it???

 

I guess that is what I was used to on other vehicles to get the light in there at the right angle. I will kick myself if all this time it has just been that tube.

 

Please follow up and let us know. They won't run if they're not piped up, for sure.

 

Did you check this splice that joins all injector negatives and ECU Pins 10 and 20?

 

Welcome to fuel injection! In addition to the vane that keeps the fuel pump running, the VAF (Volume Air Flow) meter tells the ECU the air flow, so it can set the injector pulse width, which sets the mixture. So with fuel injection, you always need to have all the induction plumbing hooked up.

 

I have checked the splice group, and am hooking everything back up after I replace all the fuel injector seals after I pinched one putting it back together last time, Replace them all (again) as long as I am in there. Will follow up and let you know if the piping fixed my issue.

 

Love this thread. Power to the internet.

Addition to other info present: the flapper door of the air meter unit has a switch. No air, no push, no switch click = no injectors

 

Actually, the FC switch just holds the COR closed, to keep the fuel pump running. You can jumper FP to B+ to keep the fuel pump running, and the injectors will still work even if the switch does not.

But without the airflow signal (VS), the ECU doesn't know how much fuel to inject. While I would expect that you could get it to fire (badly) with a "default" injection, trying to run with the VAF disconnected is doomed to failure.

 

Would like to know if you got it running??

 

OK, finally got back to this thread to update. I got it to start, had to fix a broken wire coming for the VS signal, now it starts... but I put it in gear and try to go and it has ZERO power, although the engine sounds fine at idle, and timing has been double checked and is dead on at 5. I put it in gear, try to go, and it has so little power it sputters and slowly stalls. I put it in 4 low to give it a little extra gear, and I can somewhat move it around the flat of my driveway if I keep it floored.

My first thought is I need to check my TPS to make sure it is set right. Haven't got to this as I have had other more pressing priorities like work.

Any other suggestions on what to look at?

I know I need to re-gear the diffs as the previous owner had installed 37's and had not re-geared for them...but I should at least be able to get it to go without stalling outside of 4 low. Trying to order some new injectors...but finding the low ohm (3.5ohm in that particular year I believe) is near impossible. They Ohm out fine...but who knows how well they are working being as old as they are.

 

VS signal?? What is this please.

 

Broken wire from the airflow meter, so it didn't matter if all the plumbing was hooked up. But I still have to figure out the no power.