andrewtexas123

I am running out of ideas and hoping some one knows what the problem is! 1988 Toyota Pickup with 22RE

Symptoms:
-Rough idle mainly when I am in gear and stopped. In neutral it runs smooth as soon as I put it in gear the additional load shakes the motor and runs rough. Accelerate and it smooth’s right out and pulls strong

-Intermittently rough start. The truck always fires as soon as I turn the key. Sometimes it stutters for a split second and fires right up. Other times it sputters and dies immediately then takes 10 seconds of cranking before it fires again then runs rough until I give it some gas to stay running then runs fine.

-Could be a slight miss at idle (hard to tell) but nothing when revved up




What I know:


-Compression all four cylinders within a couple psi of 170 (fresh rebuild)

-Cold start injector is spraying fuel and time switch was replaced.

-No codes and valves set to spec when hot ,

-Ignition= New plugs and wires, pickup coil in spec and air gap correct, Ignition coil primary coil res. 1.3ohm (Factory spec something like .03-.06) and secondary coil is in spec range. Could this cause those symptoms? Timing is 5* connectors jumped and then bumps to 10-12*

-Fuel system= Fuel injectors cleaned and flow tested, all clicking like normal. Fuel pressure is perfect and regulated to spec. New filter when rebuilt motor was installed.

-Intake= No leaks I smoke tested it, Vaccum is 20" at idle, throttle body cleaned, also unbolted exhaust in front of cat to check for restriction and nothing. idle rpm set to spec.

-Other= Temp sensor (for computer) works and is within res. specs, all the grounds have clean solid connection, TPS has been set up with the proper feeler gauge and resistance spec not 100% sure its good but seems like it set up according to various videos

Thanks for taking the time to read this!

Flash319

Sounds like you have covered most items. I do know the geound wires that attach to the intake bolts on the bottom ( they are red in color with a ring terminal) need to be good. It seams like you have a weak cylinder for one reason or another. I would check all the injector wiring back to the resistor on the fender. That wiring goes bad. Also check your ecu plug and wiring around there as well as the ecu itself for rotting and crap. The fender wells get rotten and water comes in right at the ecu.

Also check your o2 wiring at the sensor and check the signal at the diagnostic terminal. Allso make sure at idle your tps switch closes. If you short your diag terminal to check timig and your idle drops your tps switch is good.

andrewtexas123

The grounds on the intake are good. I checked out the ecu, even took the covers off to see if anything looks obviously burned and it looked really clean. So did the wiring going to it.

I still need to check 02 but tps closes no problem.

I also cheked a little switch in the IACV and resistance was to spec. Just did a cylinder leakage test and every thing checked out perfectly. When I pulled the valve cover off a little smoke was coming from the bottom of the case is that normal?

My plugs have some pretty good fouling it looks like. What could be the cause of this?

Flash319

Ya those are rich. Your O2 may not be working. Also could be bad cold start injector timer or injector. My plugs are usually on the white end of the spectrum.
If you run the truck up to temperature then place a volt meter from negative to O2 pin in diagnostic plug you should see the voltege swing from around .4 volts to .8 volts. If it is not swinging back and forth your sensor is ng.

andrewtexas123

I have a crappy DMM but the reading for the o2 sensor with the truck at operating temperature was switching between .12 and .70 volts.

This truck is driving me crazy haha

Edit: its interesting that plug #4 has less deposits than the rest. I haven't driven the truck enough to see if im burning oil

an1176

Check your pcv valve and grommet. I think that can cause your idle issue. I don't know of a way to troubleshoot it but it's cheap and can cause what you're having.

James Snell

Do you know that your exhaust gas recirculation system is working right?

andrewtexas123

I will replace the PCV tomorrow since it is cheap. I have heard the little ball rattle when I had the valve cover off so I think its good.


EGR seams to be seating and when I apply vacuum to the valve it kills the motor. I have also put a little sheet metal plate infront of the port into the intake manifold and no change in the way it ran. I have checked to see if I have vacuum feeding the egr and it fluctuates only slightly. I need to see if under load I have vacuum.

----------

Where I stand..

Plugs seem to be fouling weirdly with low miles and I have no black smoke like its super rich or blue from burning oil. What else could foul them ignition system or timing?

Like I said I have timed to 5 and it advances to 15. When I am timing it the light bounces back and forth maybe a 2-3 degree deflection is that normal?

MAF all resistance to spec. O2 sensor is switching and resistance is to spec on the sensor not sure otherwise

One more thing to note last time I smogged it (600miles ago) passed by 2ppm with high NOX is that a clue????

EDIT:

Tommorrow I am going to put a fresh set pf plugs in and see if that makes a difference along with pcv. I plan on smoke testing the exhast to check for leaks up stream of the cat. Also see if I have vaccum getting to the egr undel load? maybe a seperate issue?

wyoming9

iTrader: (1)

Automatic or manual ??

What is the RPM at idle in gear it almost sounds like it is set to low.

I don`t know about those things never having learned to drive the automatic Transmission

an1176

If your timing it and the mark jumps around, that's a sign of a bad TPS I believe.

an1176

Does it idle down when you jump te1 and e1?

andrewtexas123

Its an Auto and I have tried 750, 850, 950,1050 not much change all about the same.


Yes it idles down with the connectors jumped so I think TPS is good.

maco35

Any updates? I'm having a similar problem.

Flash319

Cold start injector leaking? Cold start injector system malfuntion? Faulty ignition coil? Fuel pressure regulator vacuum hose not connected to right port, or regulator NG. If you pull the hose off the regular and suck on it while the truck is running the idle will drop or you should be able to starve the engine for fuel.