Engine trouble on the DD - F-Body Road Racing and Autocross Forums

My daily driver is an 88 Buick Park Ave. Lately, I've been having trouble with it running right when the engine is hot and I restart it. Almost seems to be vapor locking, but it's multiport fuel injection. Ocationally when this happens, I can bleed some "air" or maybe fuel vapor out of the schrader valve on the rail which sometimes helps, sometimes not. It starts, then idles like it's missing badly and the engine won't rev up. So far, I've been able to coax it into working and getting me where I need to go, but I at a bit of a loss as to why this is happening all of a sudden (the last week or so). The weather hasn't been too bad lately and it was certainly hotter earlier in the summer and it ran fine. It seems OK while I'm driving and after it's been allowed to cool down all the way.

The recent maintenance includes:
new fuel filter
new plugs
new coil packs and igniton contol module
Removed and cleaned injectors (really were pretty clean to begin with)

My ideas:
fuel pump is low on pressure allowing the fuel to vaporize in the rail while sitting after driving
Bad presure regulator not holding the pressure up while sitting after driving, or sticking not allowing the vapor to exit and return to the tank.

Any insight or ideads would be appreciated.

00 SS View Member Profile	Aug 15 2011, 11:23 PM Post #1
Experienced Member Group: Advanced Members Posts: 1,197 Joined: 13-February 04 From: Hudson, Colorado Member No.: 197	My daily driver is an 88 Buick Park Ave. Lately, I've been having trouble with it running right when the engine is hot and I restart it. Almost seems to be vapor locking, but it's multiport fuel injection. Ocationally when this happens, I can bleed some "air" or maybe fuel vapor out of the schrader valve on the rail which sometimes helps, sometimes not. It starts, then idles like it's missing badly and the engine won't rev up. So far, I've been able to coax it into working and getting me where I need to go, but I at a bit of a loss as to why this is happening all of a sudden (the last week or so). The weather hasn't been too bad lately and it was certainly hotter earlier in the summer and it ran fine. It seems OK while I'm driving and after it's been allowed to cool down all the way. The recent maintenance includes: new fuel filter new plugs new coil packs and igniton contol module Removed and cleaned injectors (really were pretty clean to begin with) My ideas: fuel pump is low on pressure allowing the fuel to vaporize in the rail while sitting after driving Bad presure regulator not holding the pressure up while sitting after driving, or sticking not allowing the vapor to exit and return to the tank. Any insight or ideads would be appreciated.

00 SS View Member Profile	Aug 20 2011, 02:26 AM Post #2
Experienced Member Group: Advanced Members Posts: 1,197 Joined: 13-February 04 From: Hudson, Colorado Member No.: 197	I replaced the pump this afternoon. I now get a full 2 second prime run when I turn the key and I get 40 psi as well. It seem to run fine now, but only time will tell. By the way, never assume the pump pick is alway submersed when there is fuel in the tank. I had a hell of a time getting the new pump to prime. Of course, I was doing this with the back end up on ramps and about 2-3 gallons in the tank. It finally dawned on me and I added a 5 gallon can of fuel. Primed very quickly after that and fired right up. No matter how hard you try not to, it's still easy to do stupid things. I still seem to get an intermittant SES light, but nothing seems to be wrong. And, of course, it will never do it when I have a scanner available. That's probably the next thing I'll have to buy.