NHEngineer

After replacing the ignition ignitor unit and the O2 sensor my '86 22REC still runs like crap. It starts right off no sweat and it may run OK for a few miles or so [or it may not]. Once it starts to screw up though it runs really erratically like someone was turning the ignition on and off. It will do this anywhere from 1 minute to 20 minutes with the 'check engine' light on. The light may go off and the engine runs fine for only a short time and then the light is on again and it's back to running fast then idle, then fast then idle, and so on with the accelerator pedal position unchanged. Eventually, it will run OK until I shut it off.

Jumping the OBD connector, the codes are #3 [No signal from igniter 4 times in succession, - Defective Igniter, - Defective Main Relay circuit, - Defective ECU] and #11 [Short circuit in Check Connector T with A/C switch ON or TPS, - IDL point OFF, - Defective A/C switch, - Defective TPS circuit, - Defective TPS, - Defective ECU]. I've already replaced the ignition igniter for big bucks. The TPS is $75 and I'm OK with that if that's what it 'probably' is but I don't want to just be throwing parts at it like a gas station mechanic would [no offense intended]. I don't have AC so it's not that, I don't even know what an 'IDL point' is and a RockAuto ECU is around $350.

Anyone out there experience the same or similar deal have a suggestion?

Gamefreakgc

The TPS would be a good place to start. I'm not sure on what specs you should be looking at for an REC (not a whole lot of those on the road) but hoping someone can chime in. Sounds like it could be WAY out of adjustment and you have to put a ton of throttle before it exits "idle".

If you cannot find a manual, then just use these specs as a guideline:

http://personal.utulsa.edu/~nathan-b...34throttle.pdf

Basically, it should show a reading in ohms (usually 400 ohms or so) when closed with no throttle and once you open it about .85 mm it should give you an infinity reading.

scope103

Don't worry about #11 just yet; while it can point to a TPS problem it is also affected by whether the AC switch was on when you retrieved codes.

For #3, start at the distributor and proceed through the igniter. http://personal.utulsa.edu/~nathan-b.../4onvehicl.pdf Run the diagnostics in the manual.

For a little more background (your user name does include "engineer"), http://www.autoshop101.com/forms/h23.pdf

osv

you are clearing the codes every time that you try something, right?

have you tried disconnecting the tps, to see if the symptoms are different?

you can read some tps functions with at voltmeter, at the cpu connection:
http://forums.off-road.com/toyota-su...e-1300rpm.html

NHEngineer

If "AC" means air conditioning, I don't have any. If not, what does it mean?

OK, I'll do it and report back.

Yup, mechanical engineer class of 1965, Ben Franklin Institute of Boston.

Thank you Scope 103

NHEngineer

Idling is not the problem. It idles; kind of. Crack the accelerator a bit though and RPM will go up and down, up and down and so on. If I release the accelerator it will idle only just barely erratically. Eventually, anywhere for 1 to 20 minutes of this, it will run normally usually without any re-occurrence .......usually.

Between which terminals? There are four.

NHEngineer

Oh yeah, new coil too.

NHEngineer

Oh yeah #2, new cap and rotor too.

NHEngineer

Oh yeah #3, when it's doing this it sometimes back fires out of both the induction and the exhaust. Sorry, I should have mentioned that first off.

osv

they are labeled in the pdf link he posted... vcc, vta, idl, E2.

they can also be reached at the cpu connector also, located at the passenger side foot area, in the cab of the truck... you'll have to run extension wires up to the engine area, to plug into your voltmeter.

i'd really like to see someone test those terminals in an active state, per the link I posted... maybe i'll have to do it myself, lol

unplugging the tps connector would be a simple way to see if that's where the problem is.

NHEngineer

Yup and oh yeah #4; I did unplug the TPS connector and there was no change but I had no way to know what to expect when unplugged and forgot to mention it. While unplugged, I manually moved the throttle control and the RPM when up and down just the same way with it connected. There did not appear to be any noticeable difference.

I've been screwing around with this problem, off and on, since May and I've almost forgotten everything that I've tried. Sorry.

osv

if unplugging the tps doesn't change anything, i'd be inclined to wonder if there is a break in the wiring(or connector) between the cpu and tps... you can ring the wiring out manually with an ohmmeter, or maybe try that active test, see if you get readings on the meter.

backfiring through the intake is not a good sound... is the timing right? check it with the connector on the fender shorted?

main relay error... between the glove box and passenger fender there is a relay that can cause all kinds of issues, you can't buy 'em new, but try this troubleshooting:
http://www.4crawler.com/4x4/CheapTri...ORelayLocation

also check out the afm:
http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml

Gamefreakgc

The backfire is probably the issue for the weird RPM drops. You lose compression when the combustion happens with the intake valves open. I second the timing, sounds like you've got bad pre/post ignition or something.

NHEngineer

It only backfires when it's running erratically. After things calm down, it runs slick with no backfiring at all. It almost acts like there's water under the distributor cap ...but there isn't. I seems like there's some sensor that goes nutty during warm-up and turns on the check engine indicator and that makes the ECM change the timing back and forth. Warm-up however is not always part of the scenario though. It can start running erratically at any time only usually during warm up but not always.

NHEngineer

Well, I think I've discovered what's been causing 90% of the problem. I borrowed a distributor from a friend with a 22RE blown engine. The engine runs better than it ever has since I rebuilt it. The 10% that remains I can probably live with. That is, after about 20 or 30 minutes of around town driving, it begins to misfire a little tiny bit but there's no check engine light. I retarded the timing a C-hair and it's better but still doing it. I don't have a working inductive timing light so it was timed by ear when I installed the borrowed distributor.

What lead me to try another distributor was when last I started it and ran it under full misfire until it finally cleared up it took about 15 minutes. When it was running "OK" but not perfect I could smell something like hot metal. I got out and saw the muffler was cherry red as was the pipe leading to it. The muffler had been so hot it had actually melted at the seam. As I let the engine run a bit the muffler gradually cooled to normal temperature. That was telling me the timing had been extremely retarded for a time and since no one had moved the distributor I figured the hall effect sensor was the culprit.

Thank you all for your help. There's a rebuilt distributor and a muffler on the way from RockAuto.

osv

thx for the followup, I hope that nothing serious got damaged with that heat.

scope103

"timing by ear" is the same as "timing it wrong." A timing light is $20 http://www.harborfreight.com/xenon-t...ight-3343.html Set the timing correctly and your last 10% will probably clear up.

Terrys87

iTrader: (1)

The timing by ear can get you way off. To far advanced will get you a "Cherry manifold". Seen you mention the distributor cap. Get one from the dealer. It isnt much more then what the top shelf brand is from a parts store.

The part store plug wires just dont have a great fit and sometimes will work themselves off. I get mine from >> http://www.ebay.com/itm/250854901322...84.m1438.l2649 and that beats alot of dealer prices and really are a better brand all the way around and no more loose fitting plug wires.

NHEngineer

Agreed and I'll follow your advice a get a timing light.

NHEngineer

Yeah, I agree Terry but I had no choice at the time.

Ummm, I think retarded will cause some unburned fuel/air mixture to burn in the exhaust system, To far advanced may burn the intake valves.

I also agree. The boots from Federated wouldn't go all the way on to the plugs. Until I get some more liquid capital I think I slit the boots.

I'll check that out. Thanks.