hln111

Hi,
Bought the '91 about a month ago, 50k. Sometimes after the car sits for several hr's, while I'm at work (9hr's) it won't start. I've checked fuel pressure at the rail and injector resistance when cold and they're perfect, according to fsm. After the car is started, and as long as it isn't sitting for hr's on end, it starts and runs fine. Again, it doesn't not start all the time, just every once in awhile, but just enough to get you crazy. It cranks and cranks but won't start unless you give it a tiny shot of starter fluid, then it starts immediatley and runs fine from then on. I've read several threads but can't find one that addresses this problem specifically.
Sure would appreciate suggestions.
hln111

joe paco

needs an accellerator pump, doesn't it? fuel available, except in the intake/firing chamber. also spark.
interesting. I have a 91 and will need to pay attention. not a 'slow to start,' a no start cold without a boost.

I am new to ECM issues, but many people here are able to resolve this simple problem. (they're all simple in hindsight."

saludos, joe

stoydido

these have a "cold start valve" but don't know how it works, of if it hinders cold/fresh start or stops it. in summer, I would not guess you would need it except to save starter and battery.

have read where one thought it was no fuel at start, but it was flooded due to leaking injectors, intermittent. try holding throttle to the floor when cranking. my guess it that starting fluid overcomes the flooded condition, but I may be full of it. hee hee.

jc

JackDidley

No cold start valve in a 91.

stoydido

thanks Jack. explains why I never knew where it was. much is hidden on these engines, like ground terminals, acess bolts, oil pressure sensor, etc..
I still enjoy learning.

JackDidley

Thats why Ive been clicking on this forum for about 10 years. Still learning.

aklim

Based on the fact that your injectors are probably stock and have been sitting there for a long time, I would recommend you send it out for testing and cleaning. I do mine ever couple to 3 years

stoydido

Interesting, aklim. If a stock multec can last 100k, and there are no symptoms, why do that? may be personal preference, but not good advice for the masses.

jc

aklim

Lasting 200K is different from working perfectly. The solenoid might be functioning but the spray pattern might not be good. There is only one way I know of to ensure that the pattern and volume is good and that is to put it in a test bench. I had one injector that was at 336cc and the spec was 434. At the end I had the largest variance of 0.8cc and the next two were 0.2. Rest were matched. Based off driving, how would you notice that? Before the cleaning, I was running 336 412 412 397 418 422 433 431 for volume. One would assume that having all cylinders even would be best, can one not?

joe paco

to the guy with cold start issue, hold WOT while cranking. if it is suspected injector, buy two sets, so you can change them in a year or so (joking.)

"best" is a word, highly subjective. a multec spray is different by design than Bosch, so that's all you can say. L98 is not individual port injection, so I thought, each side fires four at a time.

if you can't tell any diff other than dyno of flow test, does it matter?
not to me.

aklim

No, buy 3 so that in case one fails and you are stuck, you have 2 other known good sets in case one of the 2 fails. I just send mine out in the off season when I don't plan to drive it for a week. OTOH, maybe it is the malfunctioning accelerator pump? I know mine hasn't worked for a long time.

What's your point? Multecs can get clogged like any other injector. L98 is bank fired but how does that affect anything?

Well, if "ok" is good enough for you, I guess not. I don't want my cylinders running lean.

hln111

Personally it seems to me that the injectors are closed and not alowing gas until it's primed with the starter fluid and then they open and begin to fire. So I ask, what controls the opening, or firing of the injectors. It happened again today after I got out of work, it wouldn't start until I gave it a shot of fluid.

hln111

stoydido

one of the experts will chime in before long. I ain't one!
the ecm triggers the injectors from signals from the distributor.

by not start, I assume it cranks for ten secs or so. did you hold WOT while cranking?

stoydido

i will add, in case...

turn key to start, FP on for 2 secs, if relay is working. you hear the pumP?

key off, wait 3 secs, backon 2 secs, maybe again, to pressurize rail. then start.

aklim

Injectors are closed as a rule and when the circuit is completed by the ECM they will open to spray fuel. If it runs the fluid start, it is getting the signal. It could be poor atomization of fuel that makes it harder to start. Again, I think you need to send the injectors out. While they are out, take out the TB and the IAC housing and clean them. Reassemble when the injectors come back. Also make sure you have no leaks in the hoses and then set the timing and IAC,.

aklim

If you hold WOT while cranking, won't it disable the injectors in a "clear flood" mode?

aklim

If you are getting good fuel pressure, why would you need to turn it on and off to cycle the pump?

stoydido

his issue in NOW, in summer, only after sitting for a while, sometimes. does not sound like all injectors are in need of rebuild. big diff betwen optimum and "no start."

stoydido

that's the point, ain't it, in case they are leaking? got that from a service tech. is it wrong?

stoydido

he does not check it in the parking lot, dude. prime the rails, what's to hurt?