Blacksmith

86 22re turbo that i just rebuilt because of low compression in three cylinders. I just recently blew a head gasket but luckly i caught it early so it did not cause any other damage. I start in the morning starts fine idles fine but after shutting it off and waiting 5-10 mins start it back up the rpms r really low. It sounds like it will die but it doesnt just runs really rough. So when im driving every once in a while it looses power like its mis firing or something. This happened before blown head gasket and i thought i fixed it with a new throttle sensor. This week im going to check timing and compression, but what else should i do or what is wrong?

wyoming9

iTrader: (1)

When you say rebuilt what do you mean ??

Bored Block as needed new pistons/ rings.

Polish/ Turn crank/ New bearings

Recondition Rods /New Bearings

New Front Engine parts Timing set/ oil pump/ cover/

Head reconditioned/ parts replaced as needed New Cam ??

New Fuel Filter??

All new Tune up
Could be rings are not seated

Vaccum hoses bad or on wrong

Timing Chain or timing off

Might be a poor connection at one of the harness connectors or a sensor

It all comes down to what you might have done or not

Blacksmith

Re machinned core dozen new hoses couple sensors. Im going to get new fuel injectors, because i believe they r still the orginal with 170,xxx miles on them.

alltracman78

I would send them to witchhunter instead of buying new ones.

Do you only have problems at idle?
It may be your ISC valve.

Or possibly your ECT[Engine Coolant Temp] sensor is starting to go bad.

Blacksmith

When i first start the truck idle is fine after 10 or min driving i shut it off. After 5-10 mins of sitting i go start it back up and it runs rough!! The last time it did this i pushed it to hard trying to get the idle right and i blew an head gasket.

wyoming9

iTrader: (1)

Could you be having fuel filter/ pump issues

The injectors on my 87 22rec have over 250,000 miles and still work good

Blacksmith

Im thinking it is just carbon build up, not running the rpms up high enough

Hadmatt54

Running rough? As in black smoke out of the exhaust? That would indicate a rich mixture and I'd have to agree with alltracman78..first place you should look is the coolant temperature sender (thw).

Blacksmith

Oh woops i thought i was on a different forum. Yea i will take a look at the (thw)

Blacksmith

When its idling and then when u try to move it bounces around like its only running on a cylinder. Then after a couple of minutes driving it doesnt do it again.

Blacksmith

How bout a smooth idle, my truck doesnt idle at one spot, the rpm gauge rises up a lil bit then drops back to 1000 then raises up 2-3 notches. Whats up with that?

abecedarian

Sounds like a vacuum leak to me. Could also be a mis-adjusted throttle position sensor.
4crawler has some pages relating to the pre-88 systems. Though it's oriented at the 22RE, the same applies to the turbo:
Timing: http://www.4crawler.com/4x4/CheapTri...CheckConnector
Throttle position sensor: http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

Idle speed should ALWAYS be set with the engine fully warmed up and is done in conjunction with setting timing... much like you'd do with a carbureted vehicle: set timing, adjust idle speed, check / adjust timing, adjust idle, etc. That's going to be hard to do if you can't get a steady idle speed. But, if you can get that squared up, some of your other problems may go away.


As for your "cold" start issue, a few things happen when cold starting:

When you turn the key on:
1) voltage is applied to the idle air valve connector and starts heating a bi-metallic strip inside. This strip starts closing the IAV. Below 65F, the IAV should be at least partially open, allowing air to bypass the throttle plate and raise the idle speed when the engine starts. The colder it is, the more open it will be thus the higher it should idle. Normally though, it should not idle higher than around 1600 rpms and should come down fairly quickly once the engine is running- should be near stock idle speed (750, I think with yours) within a few minutes.

When you crank to start the engine:
1) the ignition switch turns on the circuit opening relay, which in turn activates the fuel pump thus pressurizing the fuel rail;
2) voltage is applied to the Cold Start Injector Time Switch (brown plug on forward end of intake manifold) and if it's < 65F (give or take), the CSTIS passes voltage to the cold start injector which injects additional fuel to help cold starts;
3) ignition timing is set to baseline for easier cranking and starting.
4) starter spins
5) engine starts and you release the key

Once the engine is running and you release the key:
1) voltage to the COR from the ignition switch is cut off. However, the air flow meter keeps the COR on, thus the fuel pump continues running
2) voltage is removed from the CSTIS which in turn causes the cold start injector to shut off.
3) cold running fuel enrichment is handled by the ECU adjusting the primary fuel injectors' pulse width according to the coolant temperature switch / sensor (green plug on the forward end of the intake manifold).
4) ignition timing becomes dynamic, controlled by the ECU according to rpm, coolant temp, ambient air temp, intake air flow, etc.
4) coolant begins flowing through the IAV. Coolant temp will override heat from the bi-metallic strip opening the IAV if the coolant's cold but the strip is hot, and closing the IAV if the strip is cold but the coolant is hot.
5) when the engine is fully warmed, the IAV should be fully closed. The ECU controls idle speed by adjusting engine timing.

Judging from your OP conditions, #4 and #5 directly above may be part of your issue: the IAV isn't operating properly. This is not surprising on an older vehicle- even my 88 has some idle issues but I'm just lazy and haven't fixed it since it works relatively well in all but the coldest situations... like below 45F, and I rarely have that here in SoCal.

knucklehead38401

I can ultrasonically clean those injectors and get them like new again!

Blacksmith

Well i think my injectors are past the point of repair because they are falling apart