Hi from the UK guys,
I know this has been mentioned a zillion times before but hopefully someone will have a few pointers for me to look at....here's the deal....
I have an 88GTA, 5.7L TPI (Auto trans)....during the warmer months of the year it starts really hard, cranks for maybe 10-20 seconds then slowly "winds-up" until it starts. After that, it runs fine. If it is left for a long period of time (overnight for example) it exhibits the same problem. If it is left for a short period, say an hour or two it will crank a lot less, then fire right up and run fine. Since I had the car, nearly two years ago, the idle has always been a little "up and down"....nothing major, just a coupla hundred revs difference as it idles...but it runs fine....all these symptons are maybe a fuel pressure issue right???
However, heres the bit I cannot understand....now it has got a bit colder over here the car will fire right up from cold, then it will die if you do not pump the gas a little....it'll do this maybe twice, then it will idle...if you pull away in it just after starting it runs like s**t, spluttering and bogging down momentarily, then it pulls away fine...as it starts to get warm, if you come to a stop, it will idle faster than normal, about 1000 rpm (usually about 650ish), slowly dropping if you remain stopped (I am also getting c**ppy gas mileage at the moment!!)...when it gets warm this problem disappears!...it also will go back to normal idle if you give it some gas and let it come back down again....after it gets up to temp it runs okay...still has fluctuating idle of 200ish revs but that is all.
So, at the end of all that....any ideas of what I should be looking at guys?...I have only replaced the spark plugs, leads and CTS engine wise since I had the car and it is not showing any codes at the moment....any pointers on where to go from here would be gratefully appreciated on this side of the pond...my dad has a F**D....I only like to drive that in emrgencies!!!!!!!!!!
Thanx for reading this...
Jon

 

Jon,
A couple of things possibly:
1. Fuel pump could be getting weak, check your pressure at the schraeder valve on the passenger side runner.
2. Is your cold start injector working OK?
3. You might have leaky injectors, (seriously doubt this one).

Where in the UK?, I am a naturalized US citizen from Sussex

Good Luck

Cheers

Richard

88 GTA w/a 350, ported plenum etc etc etc...

 

Thanx 88gta305....I'll check 'em out...would the cold start injector be a problem do you think?...I would've thought it would not start BETTER in the cold weather if this were at fault...tho' I'm not sure!!...

FYI, I'm from Rugby, Warwickshire (near Coventry & Birmingham???).

Anyone else got any ideas....?

 

BTTT............

 

UK,

The cold start valve only operates briefly to help get the engine started. It does nothing once the engine is running, since it only operates during cranking.

Your description of the rest of your symptoms indicates a fuel delivery problem. A quick test of the fuel rail pressure might reveal a lot. The poor performance when cold, difficult starting, failure to idle once started, etc., all could be the result of low fuel pressure - just as the protracted cranking before starting.

Get a fuel pressure gauge (or old refrigeration low-side pressure gauge) and connect here:



You should generate 260 KPa (37 PSIG) at idle with the vacuum line connected to the regulator, or 300KPa (44 PSIG) with the engine stopped or the vacuum line disconnected. There is a +/- 20KPa (3 PSIG) allowable range for those specifications.

------------------
Later,
Vader
------------------
If you want to beat the World, it might reach up and pull you down...
Adobe Acrobat Reader

 

Thanx guys....I will check out this as soon I can take the car off the road for a bit...may have to drive the f**d after all!!!
Time for a new fuel filter (at least) I guess!!....
Thanx to all you guys over there...you really are invaluable to all us far flung third gen owners!!!

 

Sounds like fuel pump relay is defective or has dirty connector. The relay energizes when you turn key on for about 4 seconds to build fuel pressure. After engine is running the fuel pump gets it's 12 volts from the oil pressure sender switch. Your problem is exactly the the way these cars act with a bad relay. Your cranking the engine will build enough oil pressure to close the switch and turn on the fuel pump, usually after about three or four cranks(depends on viscosity of your oil). Have somebody stand at the rear of the car after it has sat overnight and listen to the whine of the pump when you first turn the key. If no whirr is heard suspect the relay. Hit the connector with some contact cleaner, it may be all you need to do. Dan, 89 IROC 1le

 

Danno,
Thanx for the advice but the pump does run when the ignition is turned on....will clean up the relay nonetheless but I think darker forces are at work!!!!

 

TOO LONG, I'm not reading it.

------------------
Yo MAMA!

 

I will be as short as possible. Next thing, any trouble codes. Mass air flow relay, MAF burnoff relay or bad sensor will cause these problems(sensor big bucks). Normally you will throw a code. One VERY common problem is a dirty throttle body. Suggest you take it off and clean it WELL. also take out IAC valve and make sure everything is clean. Most everything of a serious(and expensive) nature will identify by a code. It has been my experience that the little S*** causes the most grief. So Long for now, Danno