:bouncy: :crybaby: hi Brooklyn tony here; my 96 eldo is hard starting ,after engine is at operating temp then shut down from 15minutes to 2 hours, it takes 3 seconds sometimes more to start. it cranks over quickly then starts, no fuel smell,doesn,t run rough when it starts, sometimes I hear a backfire in the intake manifold.I have since replaced the fpr because it was leaking fuel into the intake manifold.the car has 65000 miles, I replaced ignition wires,a/c dual plat plugs, pre cat oxygen sensor k/n air filter, battery. that backfire still occurs from time to time only after engine is warmed up. starts on first crank when engine is cold even after a 3 week lay over .the engine always runs smooth with plenty of power. the fpr is not leaking., is it an ignition problem? cadillac said it is a sensor in the fuel tank? dont sound right to me/ I am only having this problem in the time frame above any info would be appreciated thanks:tisk: the back fire only occurs during crankingwhen engine is warm[sometimes]

im not too sure but maybe spark plugs? :hmm:

sorry, i dont really know much else that could be the problem...

-mir

Have you checked for a leaky fuel injector?

HI RANGER, I thought of maybe one injector leaking but I figured if one or two were le aking that would affect the fuel pressure on the rest of the system then I would have hard starting the following morning,I assumed wrong by Your answer. the question now is,the easiest way to check for this leaky injector , should I warm up the engine then pull each plug until I smell or see fuel. again thank you for answering my post .

To check for a leaky fuel injector, pull the fuel rail with the injectors attatched. Then turn the key on but do not start. That will pressurize the fuel system and you can see if an injector is leaking.

HI RANGER, I will pull the fuel rail and get back to you asap,Thank You again. Brooklyn Tony.

HI RANGER, I will pull the fuel rail and get back to you asap,Thank You again. Brooklyn Tony.

Tony, let me know what you find.
A friend also has a '96 ETC with the hard to start problem,after he did the feul rail recall ever since he has had the hard start,no leak at the FPR,new plugs and wires,feul pressure is at 45 running and with ignition on only jumps up to 53 w/no vacuum,it takes about 10-15 minutes to loose pressure after i shut her down.
I'm about to yank the feul rail and check for a leaky injector myself,i'll try doing it tonight and post my findings.

Pete

HI RANGER, I will pull the fuel rail and get back to you asap,Thank You again. Brooklyn Tony.RANGER one more question, do I leave the electrical connectors attached to the injectors while I perform this test. Thanks BROOKLYN TONY

HI PETE ,BROOKLYN TONY HERE, I will post my results as soon as I find out.

RANGER one more question, do I leave the electrical connectors attached to the injectors while I perform this test. Thanks BROOKLYN TONY
Yes.

HI RANGER, I put a sheet of paper under all injectors,pressurized fuel sys for ten mins, then turned ign off for thirty five mins, no fuel drops on the paper,but I did notice slight wetness on two injectors. the engine was cold on this test.should I perform this test with engine at operating temp,Is it advisable to use Lucas fuel inj cleaner? Thanks BROOKLYN TONY.

If it didn't leak in :35 min they are ok. Hot or cold shouldn't matter. I wouldn't fool with injector cleaner. Bbob says that stuff can damage the windings. I would have thought FPR or leaky injector. I'm lost. This sounds like one for the master. Maybe he has some ideas.

HI RANGER, I put a sheet of paper under all injectors,pressurized fuel sys for ten mins, then turned ign off for thirty five mins, no fuel drops on the paper,but I did notice slight wetness on two injectors. the engine was cold on this test.should I perform this test with engine at operating temp,Is it advisable to use Lucas fuel inj cleaner? Thanks BROOKLYN TONY.

Hey Tony
I just did the same test to my friends Eldo no leaks holds pressure,no leaks at the FPR,i took out the IAC cleaned it up and also cleaned the ground on the side of the ignition coils,and ohm'd a couple of spark plug wires they checked good,i will try to start it tomorrow to see if any of these things fixed the issue.
The one thing i'd like to change is the temp sensor.

The last thing we did on this car was changed the plugs AC Delco and Bosch wires,a day later it went in for the feul rail recall when we got it back it started the hard start.

Let me know if you find anything,i will be posting my progress and hope to figure this out.

Pete

HI RANGER,PETE, I put everything back last night, drove car to operating temp and let it sit for 45mins it started onfirst crank, then tried after 2 hours, again started on first crank, now today drove 15 miles, parked car for 35minutes, no start for 3 seconds cranking, turned off ign switch then tried to start again,this time started after a few cranks. I could be wrong,but it sounds like weak ignition, I dont hear that hearty compression snap like I hear when the engine is cold.I hope I described it so YOU can understand what I mean.I will try cracking the throtle about an eight of an inch as I crank the engine when warm and see if it makes any difference,I will keep YOU informed thanks BROOKLYN TONY.

I think you need to get a fuel pressure guage and put it on the fuel rail schreader valve every time you suspect this may happen and watch the pressure berfore and during cranking. It should be 45-50 psi and remain relatively steady during cranking. You may have an intermittent bad connection at or in the fuel pump and the pump is in it's final stages.

Tony i'm leaning towards a weak spark myself since this was the last thing we did and the problem showed up.
If i get a chance tonight i will look for codes and history,even though i don't get a SES.

I might even try a new set of plugs and AC/Delco wires just to see what happens.

I've had the feul pressure gauge on all day even when it had hard start it had good pressure.

Pete

OK RANGER, I will buy a gauge and check the pressure,and let you know, thanks

Fuel Pressure Regulator.

It's the 'thing' just before the first injector. With the car running, pull the vacumn hose off of it. If fuel leaks out, it needs replaced.

Well, i checked for codes no present codes the only thing i got was from history an O2 sensor.

I will have to backtrack maybe change wires and plugs.

LCLCLC, I already checked the FPR and for leaky injectors all check out good,read previous posts.

Tony i'm leaning towards a weak spark myself since this was the last thing we did and the problem showed up.
If i get a chance tonight i will look for codes and history,even though i don't get a SES.

I might even try a new set of plugs and AC/Delco wires just to see what happens.

I've had the feul pressure gauge on all day even when it had hard start it had good pressure.

Pete

I agree with new wires. The problem all along may have been faulty ignition wires. Sorry I did not see this thread earlier. I would use OEM plugs and OEM wires ONLY. Don't listen to any fancy talk about anything other than what the manufacturer recommends. Use ONLY genuine GM replacement plugs and wires.

HI BROOKLYN TONY here,Just a quick update, RANGER I didn,t getTO CHECK THE fuel pressure yet but I will. I have been USING the car more often than I USUALLY DO and the engine starts within one SECOND OF CRANKING BY TURNING THE KEY ON FOR APPROX 3 SECONDS,SLIGHT CRACK OF THE THROTTLE ,THEN STARTS WITH NO DELAY.PETE ANY UPDATE ON YOUR ELDO,I WLL CHECK THE PRESSURE ASAP AND GET BACK TO YOU AND RANGER .

That is a sign of a weak fuel pump. By turning the key on for three seconds you are running the fuel pump and pressurizing the system. Assuming all other fuel system components are ok (filter, FPR) then I would suspect the pump but a pressure guage will tell.

Tony, still nothing.
This is a friends car that has 125k miles.
I chagned the spark plugs with no result,he doesn't seem to think it's the spark plug wires since they are only 1 YO,the wires are not OE's but has good spark and ohm good.

So i'm all out of idea's.
I have checked everything that i mentioned above with no results.

If i ever figure it out i will post the fix.

Wish us luck.

Pete