Cleaned my iat and at idle it sounds like my injectors are pre-loading the cylinders with fuel for the first 30-45seconds after starting the jeep then the idle goes back up to normal. When it first starts revs are lower then they use to be so no sky rocketing idle at start up now but after that it stumbles. What would cause this and what am I missing?

 

IAT or IAC?

Edit: Oops, I now see you have a 1989. This is best left to the RENIX experts.

 

Where the hell are those guys? SOBs.

 

LOL

Ohh Rochester...

Coming Mr. Cruiser..

 

Vacuum leak in the throttle body to MAP piping?

 

I have rubber hose on a few pipings not sure what they go to tho lol. I did remove the vacuum hose on the fpr and didnt notice a difference in idle even reved up fine now that I think about it may have idled smoother with the vacuum line off of the fpr.

 

Low vacuum will tell the MAP that the engine needs more fuel.

Did you get the vac line for the MAP back in the correct hole on the throttle body?

 

Yes I did

 

Anything else I should look at? Also I ate thru almost half a tank of gas in 50 miles or less driving like normal.

 

Check the connection at the MAP sensor and make sure a connector hasn't retracted or something. Wiggle wires/harnesses/plugs at idle and see if anything changes.

 

Ill give it a try tomorrow since Im off and let you know what happends

 

TESTING THE EGR VALVE FOR 87-90 4.0 ENGINE

Valve Opening Test

1) With engine at normal operating temperature and at idle,

rapidly open and close throttle. Open throttle sufficiently to obtain

at least 1500 RPM. Movement should be noticed in EGR diaphragm.

2) If diaphragm does not move, probable causes are: faulty

vacuum signal to EGR, defective EGR diaphragm or defective

backpressure sensor diaphragm (if equipped), or leaks in vacuum lines

or connections.

Valve Closing Test

1) With engine at normal operating temperature and at idle,

manually depress EGR valve diaphragm. RPM should immediately drop,

indicating that EGR valve is not leaking and had been properly cutting

off exhaust gas flow at idle.

2) If there is no change in RPM and engine is idling

properly, exhaust gases are not reaching combustion chamber. Check for

plugged passage between EGR valve and intake manifold.

3) If engine idles poorly and RPM is not greatly affected by

manually moving diaphragm up, EGR valve is not closing off exhaust gas

flow. Check for carbon between pintle, leaking EGR valve gasket or bad

EGR valve.

***************

 

Ok new problem the vacuum line from the MAP sensor to the throttle body is busted at the throttle body. How do I fix this

 

Heres the pics of what and where its broke. My idle is **** now very very rough just barely idling :/

 

Isn't that what I suggested in Post #7 for crying out loud?????????????

LOL.

Pop the rubber plug out of the TB. Get the remaining piece out of the plug. Glue, without covering the hole in the tube, the tube back in to the plug.

Installation is a reversal of removal.