Need help with SC '99 Ultra

[V6TA-MI]

I am having serious trouble getting our '99 Park Ave Ultra to run at all. Car has 150k on the clock. It is running very rich when I can get it to start. It will idle with new plugs for a while then fouls them out and stalls. It sets no engine codes. The following has been tried:

1. compression is within 5 psi on all cylinders
2. new crank sensor
3. new coil module
4.fuel pressure is within spec
5. fuel pump module works fine in my son's '98 SSEI
6. all injector wires were checked with NOID tester and work to spec
7. relitivly new Delco plug wires (no more than 10k mi on them)
8. drained fuel tank and replace fuel filter.
9. gone thru the "no start" diagnostics in the factory manual with no conclusion
10.Swapped MAP sensor with a suspected good unit

I can swap sensors between the SSEI and the Ultra, not sure where to begin

Any help is appriciated.

 

[steveX]

This might be a leaky injector. you will need to perform an injector leaky down lest. you will need a fuel pressure gauge. attach the FPG to the fuel rail. start the car, watch the FPG, should say 50-52psi. Now shut off the engine. the FPG must still be connected and holding pressure(do not relief the pressure in the gauge). Now that the gauge is holding 48-52psi. watch the FPG for 10 minutes, if you notice the fuel pressure falling, then you might have a set or a leaky injector.

fouling of the plug may be a cause of excessive fuel, which i have seen happen on s/c engine.

I love the park ave ultra. it one of the next car in my collection. yea, it will be s/c. i love big cars, and the park ave is the best.

 

[garyk1970]

unplug mass air flow sensor at idle,if idle improves,replace maf.they will go bad without codes,seen this too many time to count.HTH<gary.

 

[V6TA-MI]

I did the fuel press check by cycling the key a few times til the presure was up to 50 psi. did not leak down.
I'll try with new plugs and see if I get a diff reading

I'll try swaping the MAF with the SSEI and see if that helps

Thanks for the help

 

[Brad Zeidler]

Take the gas cap off, disconnect the return line from the injector rail, use an air hose set to about 20 psi and blow into the line and see if a buddy can hear and feel the air coming out of the tank. What kind of pressure do you have while it's running? Do you get boost while driving? Check all vacuum lines and fittings that they're not cracked

 

[V6TA-MI]

Take the gas cap off, disconnect the return line from the injector rail, use an air hose set to about 20 psi and blow into the line and see if a buddy can hear and feel the air coming out of the tank. What kind of pressure do you have while it's running? Do you get boost while driving? Check all vacuum lines and fittings that they're not cracked

Thanks for the thoughts. I'll check for a plugged or restricted return line. If I can get it to idle I'll, check for vacuum leaks. Currently I can't get it to run long enough to back down the driveway. No boost gage on the Ultra, I can jurry rig a gage if I get it to run well enough to drive it.

 

[SRGN]

Possibly plugged cat, or bad coolant temp sensor giving cold start enrichment after warmup.

 

[V6TA-MI]

Possibly plugged cat, or bad coolant temp sensor giving cold start enrichment after warmup.

Cats been gutted (don't tell anyone), I'll check the temp sensors

 

[V6TA-MI]

Found an intermitant short to ground in the injector harness. Will know in a few days if that is it. Thanks for the help! I'll post the results after the harness fixed

 

[V6TA-MI]

Now there is a "anti theft system fuel enable circuit fault" Seems a dealer only fix either ignition switch module or PCM. does this seem right?

 

[V6TA-MI]

Well, after a local shop screwed around for a couple months.
I took it to the dealer, they had it for nearly 6 weeks.
new parts
PCM
Ign switch
maf
intake gasket
plus fixing stuff the local shop screwed up
$1700 later the car is home. dealer said it has a lasy o2 sensor.
Wife said the check engine lite came on tonight. I'll look tomorrow, hopefully its just the o2 sensor
Sheesh

 

[LeSabre T-Type]

i am kinda suprised the o2 wasnt the first thing you checked. oh and if it is bad dont go with bosch. stick with delco and NGK