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miamimark

it cranks, does not like to start

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I have an 89 Riviera that cranks easily, but usually takes about 4-5 times to actually start up. This happens when the engine is cold. Once it is hot, it starts the first time.

Before going further, let me add that if the car sits for several days (3,4+)without driving, it starts the first time.

Thus far, I have replaced:

the sparks

the wires

air intake sensor

fuel pump

pcv valve

fuel pressure modulator.

The car still does not want to start. There are so many sensors, that it's hard to know where to begin.

Anyone had a similar problem?

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Mark,

Sears sells a good quality fuel pressure gauge for about $50, it is an excellent place to start! An engine needs three things to start, fuel spark and compression. The last one is either there or it isn't, so it can't be your issue. You now need to determine what you don't have, fuel or spark. My money is usually on fuel, hence the pressure gauge suggestion.

One way I have used to diagnose a excessive crank problem is to not crank the engine over! When the car exhits the issue, turn the key to off and wait about 10 -20 seconds. Key the ignition back on but don't crank the engine. Repeat the above process one more time, only crank the engine over when you are done. If it fires up, you are loosing fuel pump prime which could be caused by a fuel pump, fuel pulsator, fuel pressure regulator or a leaking fuel injector.

Your car has a strange twist in that it fires up after setting a number of days, which really doesn't fit the no fuel pressure scenario, which is why the pressure gauge would help with the diagnosis. Keep us posted!

Tim McCluskey

ROA 9686

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Usually, a weak fuel pump (or not enough pressure SOON enough) will cause extended crank time, but it'll be there all the time rather than just during more frequent useage of the vehicle. I concur, it seems to be happening "backward" from what is normally seen.

There were some years of the Buick V-6s that had different ignition modules on them. It's been a while since I looked at that stuff! But there was one deal where it was a unitized (all six spark plugs) coil set-up and the other one had three separate coils (2 plugs run by one coil). One of them was more trouble-prone than the other one, but I don't recall.

As the fuel pressure should be good with the replaced parts, which the pressure check Tim is recommending would verify, plus "leakdown" rates when the engine is turned off after running a few minutes (there should be a time delay for the fuel pump if you just turn the engine on and don't start it that will automatically turn the electric fuel pump off--it might be as soon as 45 seconds and it might be a little longer, I don't recall specifically.

But as the startup after not running for a few days is the situation, but extended crank time during more frequent use is the operative situation, it could well be the ignition module, located under the coil or coil packs. I believe it's one unit, regardless of which coil set-up is used, though, and it seems like it was about $150.00 the last time I knew of them--not inexpensive, but necessary for the coils to do their job . . . just like in a GM HEI distributor (which was more reasonably-priced).

The other question might be as to how much power the engine has after the extended crank time starts and after the extended "idle days" starts? If it's the same, under moderate-to-full power situations or not?

Just some thoughts,

NTX5467

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Mark

I have three 89 Riviera's i have found that the coil pack can get cracked and this lets moisture in at times causing long crank or no crank-start.

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