2001 LS8 starts hard when warm *please help*

[rcvxl14]

I know this topic has been covered before on here, but I'd rather start a new thread than post on a old one. My lincoln ls starts really hard mostly when its warm and has sat for 1-3 hours. It usually cranks for about 3-5 seconds before firing up. When it's cold outside or when the car has sat overnight, it starts right up. However, when it's an unusually warm day or its sat about 1-3 hours, it starts hard. To me it definitely sounds like a fuel issue.

Here is a list of parts I've replaced:
-8 brand new fuel injectors
-8 brand new visteon coils
-brand new coolant temp sensor
-8 brand new spark plugs (I checked the gap on all of them)
-drivers side catalytic converter (pass. side was in good condition)
-brand new fuel filter
-MAF sensor has been tested/cleaned
-throttle body has been cleaned
-good compression on all cylinders

There is a strong smell of gas when it starts, and it is getting poor fuel mileage (15.3mpg according to the digital display in the instrument cluster). Once started, the car runs normally with no issues. I checked fuel pressure after installing the fuel filter and it was around 30-35psi. Somebody please help, it feels like I have tried everything and gotten nowhere. Any info/advice is greatly appreciated. Thanks

 

[joegr]

Well, your IAC is one remaining possibility. You might also double verify that it isn't your MAF by unplugging it before trying to start the engine.

You could also check your fuel pressure when trying to start it while the engine is warm. There might be something going on with the fuel pressure sensor. I doubt it would be the fuel pump, it shouldn't care if the engine is warm or not.

Check engine light on? If so, what codes?

Connectors tight on all injectors and all coils?

I assume that the problem started and then you replaced all the things mentioned. If this is not so, and the problem started after you did the replacements, it would help to know that.

It could be the PCM itself.

 

[Telco]

Another possibility, you have two different problems. The solenoid may be worn and getting heat soaked, then the slow start is flooding the engine. Once the engine starts and burns off the flooded cylinders, the engine runs OK. Mileage would be failed O2 sensors, replace with factory injectors.

 

[rcvxl14]

No check engine light on, I've tried unplugging the MAF sensor, no difference. I've also checked the coils/injecters and they're all plugged in correctly. Checking the fuel pressure when warm is probably the next logical step.

I've had this problem ever since I bought the car and since then I've tried fixing it.

 

[rcvxl14]

I was messing around with the EGR valve on it and I realized that it doesn't have vacuum all the time. Is that normal?

 

[joegr]

I was messing around with the EGR valve on it and I realized that it doesn't have vacuum all the time. Is that normal?

Gen I, yes. An electric solenoid valve controls vacuum to the valve according to the wishes of the PCM. (Gen II has the solenoid valve built into the EGR valve assembly.)

 

[Telco]

O2 sensors won't necessarily set a code when they go bad.

 

[rcvxl14]

O2 sensors won't necessarily set a code when they go bad.

I did have one go bad and it set the CEL.

 

[Telco]

I have too, but then I've also had them go bad but still pass the computer's test. The symptom was crappy mileage. Replacing the O2s with new factory made units restored mileage. I suggest not using the Bosch ones even though some folks have luck with them, as I've lost mileage using them as replacements.

 

[clubairth]

Check your fuel pressure. Does it fall off fast?? Maybe a injector is leaking down?
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[rcvxl14]

Ill try and check fuel pressure this weekend, I've been really busy.

 

[rcvxl14]

Well after a year of buying new parts and constantly being disappointed, i finally fixed the damn thing. Turns out i was right by buying the first thing i tried: the injectors. I replaced injector #6 recently and it is now fixed. Apparently i got a bad injector when i bought them the first time, which has caused me to waste a good 1,000 to 1500 dollars replacing parts that were fine. I learned a good lesson - DONT BUY REMANAFACTURED PARTS. The brand of the bad injector is GB remanufacturing so buyer beware. I replaced it with a brand new GP injector from Autozone. Just wanted to post this to make sure I didnt mislead people with my bad experience and cause them to waste their money like i did.

 

[SoulSoak]

Well after a year of buying new parts and constantly being disappointed, i finally fixed the damn thing. Turns out i was right by buying the first thing i tried: the injectors. I replaced injector #6 recently and it is now fixed. Apparently i got a bad injector when i bought them the first time, which has caused me to waste a good 1,000 to 1500 dollars replacing parts that were fine. I learned a good lesson - DONT BUY REMANAFACTURED PARTS. The brand of the bad injector is GB remanufacturing so buyer beware. I replaced it with a brand new GP injector from Autozone. Just wanted to post this to make sure I didnt mislead people with my bad experience and cause them to waste their money like i did.

Congratulations on fixing it. Personally I would have just bought a new LS and just drove your current one in the winter lol.