Thought I’d ask you guys that know these little 2.8 V6 engines.

the car I bought supposedly has a rebuilt .20 over 2.8 and rebuilt 700R4. was a 10 year unfinished project for the sellers son and him.

car is running rich and fouling plugs to the point it won’t start anymore. I put in a new set of plugs 3-4 weeks ago. I have been starting it and letting it run for 10 min on weekends. Has about 40 minutes of run time on it and had a hard time starting today. Had to feather the throttle for a couple min till it warmed up enough to idle. 60 degree weather

The idle also never drops below 1,600 to 1,700 rpm and is smooth

I cleaned the maf with maf cleaner no change.

Faulty maf, fuel regulator or 02 censor?

I don’t want to spend much money its getting a ls t56 magnum. If its pricey it will most likely stay that way
Unless I find a good deal on used parts

appreciate the help

 

Your first check should be to pull the vacuum line that connects to the fuel pressure regulator and check for raw fuel in the line (even the smell of fuel means the regulator is leaking). This is most easily done by pulling out the black fitting on the throttle body that has the large and small hard plastic tubing connected to it.

 

Thanks. did this did not smell any fuel.

 

With the vacuum block unplugged from the throttle body, try turning the key to the run position to let the fuel pump do it's two second prime and see if gas comes out. If not then the regulator is likely OK. A stuck open cold start injector could cause an excessively rich condition, as well as a failed coolant temp sender. The CTS that the ECM uses to set the fuel mixture based on engine temperature is on the front of the lower intake manifold, it's the smaller of the two. Doing an ohm check of that sender both hot and cold may prove the sender to be bad (I don't recall what the ohm readings should be, but a search should turn them up) .

 

thank you for your help. I don’t usually fool with this efi stuff.

I did what you described and no fuel at all.

guess i will look into that cold start injector and thermostat censor next

 

Yes the CTS and the CSI are both good things to check. I'm kinda running out of things to suggest that could cause an excessively rich mixture, so hopefully one of those is it. Another thought is that I have seen a MAF failure that didn't trigger the check engine light, but that caused a rich mixture coupled with poor running......

 

I went ahead and ordered a temp sender and also a cold start injector block off kit for a tpi 305/350 v8 apparently they fit except for the fuel rail plug. But a Dorman oil drain plug part number 090-038CD will fit the fuel rail. Cost me $27 bucks on ebay for this stuff. Cheap enough to take a chance on

CSI delete should be okay I live in Az. Coldest it gets in my area is usually 50s early morning and just need to start car to move it around property before the swap gets done. It started great in this weather with the new plugs before they started to foul.

i’ll report back.

https://www.thirdgen.org/forums/v6/775043-cold-start-injector-delete.html

 

I replaced the temp sender in the front intake manifold. There is no change.

next best move the cold start injector?

 

Since you bought the CSI delete, sure try it. As to the fan, I'm curious, does your car have AC ? If so, putting the heat/AC control on "MAX AC" should turn the fan on. Three things can turn on the fan, the HVAC control, the ECM, and also the temperature switch in the passenger's side (R.H.) cylinder head. Try grounding the dark green/ white wire connected to the temp switch (with the key on) and see if the fan runs.

 

I wasn’t waiting long enough. It turns on at 230 shuts off at 215 according to the stock gauge.

 

If you delete the CSI you might have a hard time to get it started whenever the motor is cold even if tyoure not in a cold are... im in hawaii and it wont star icely with the csi disconnected......

. I think a simple way to see if the CSI is working well / leaking would be to disconnect the electrical connector when cold and try start.. you'll probably need to crank for a bit and give it some gas to start. You MIGH have to reprogram the chip to eliminate that issue.

 

Sidenote, id repalce the FPR just because its so old... i did mine and even though it was "ok" it made EVERAYTHING even my throttle response so much better.

 

Hi 1989karr,

If the cause of his running rich with a persistently high idle is that the CSI is leaking, unplugging the electrical connector will not stop the leaking. If it is in fact leaking, the only way to stop the leak (other than a new CSI, which as we know is unobtainable) is to remove the pressurized fuel source to the CSI

 

I was thinking more that if he unplugged it, and it took a long time to start when "ice cold" that it would show if its leaking or not... that and throwing a pressure gauge on the rail?

If the gauge doesnt hold pressure well then im thinking that would indicate a leaking CSI too... it might be a pain trying to get in there to remove it! lol

 

Didn't Cruzin Performance or SouthBay used to clean cold start injectors?