Cor

Hello everyone,

I hate to post a new thread over this, but Im pretty stumped. I have a 89 5.0 EFI which I've owned for around a month. Its got some issues but the one Im working on at the moment is its trouble starting on the first try.

When I go to start: I turn the key and let the fuel pump prime (I can hear it), then on the first crank the truck cranks for a long time then finally starts. After this it stalls in about 5 seconds (unless I give it gas, which I have to do several times, and doesn't prevent it from stalling). After the first try the truck starts right up, but has very high revs (which eventually come down). After this second try I smell gas and the truck runs rich (getting bad millage). It does this second start regardless if the truck is hot or cold, first start of the day or not.

Things I have tried:
-Pulled the codes (Engine off): First set of codes say system is fine, second set of codes (from what I can tell) don't make any sense (haven't matched anything I've found. So not sure if I'm reading it wrong or what.
-Replaced fuel filter.
-Cleaned/ Replaced IAC.
-Replaced FPR.
-Replaced Ignition Coil.
-Replaced starter (it died).

Possible issues?
-Bad MAP sensor?
-Exhaust leak? (not sure if this would cause a problem, but I do have a cracked exhaust manifold on passenger side (which may be causing bad mpg. Also not sure if this crack would cause O2 sensor problems.)
-Bad coolant sensor? (Temp gauge usually reads at N on Normal, but usually runs very cold according to gauge).
-Spark plugs? (may explain why it ran better with new ignition coil)
-Fuel pump? (I tried priming the system several times before starting, but made no difference).


So, I'm sorry if this is long winded, but Im somewhat stumped on what the issue could be. Any and all help would be appreciated.

Thanks!

Update: Spoke with a friend at work and he suggested it may be a fuel injector leaking on me, Ill check that and update this if that turns out to be the case.

sam29078

Coolant temp sensor is my guess. Can you read data on on scanner? What the temp when you start truck? -40 it is bad

Cor

Thanks for the reply Sam! Unfortunately all I have is an obd2 scanner (I believe this truck is obd1), so I will look into picking one up so I can test it.

Update: I was talking to some mechanics at work the other day and they suggested I check the oil pressure sensor and the crank sensor. Would failings in these sensors cause the problems that I'm having?

94_f150_ga

I recently picked this up from Summit for $23:

http://www.summitracing.com/parts/ino-3145/overview/

Has a nice digital display vs. having to interpret flashing lights on the cheaper ones.

It sounds like an injector problem to me..I've had a no-start situation on my '94 when warm which was solved by replacing the coolant sensor, but not when cold.

Cor

Thats an interesting reader 94 f150, Ill have to look into one of those!

And it does look like it may be an injector problem. I tested the fuel pressure the the other day after getting a gauge, at it showed a slow bleed off of pressure after turning the ignition off. Then last night I pulled the injectors and found that one (mine have plastic tips on the ends) was cracked. So I think this was causing the leak.

Question: would charging/ pressurizing the fuel system without having the injectors in the engine cause damage to them or the fuel rail? I want to charge the system to see if the replacement fuel injectors have fixed the leak or if a slow bleed down is still going on.

Cor

Update: Figured Id go ahead and update this thread incase anyone else is having the same issues I am.

I pulled the fuel injectors (two of which had cracked ends) so these may have been the cause of some of the fuel bleeding off at the rail. I replaced them with different injectors, tested them to make sure they were not leaking, and put everything back together.

Still having some bleed off at the rail (maybe a tank return valve), but the truck seems to run better. Still having the second start issue so I guess Ill start looking at sensors next.

Chris_1

iTrader: (1)

What was your pressure at before it bled off ? And how long did it take to bleed down ?

Cor

Chris, the pressure at the fuel rail after priming was 38 to 40 psi. After that it would bleed off but very slowly, perhaps 1 psi per minute and eventually bleeding down to 0.

Interestingly, I did a coolant flush the other day and that seems to have fixed the second start issue for the most part. Though it will still second start if it sits too long (more than several days).

At this point I'm thinking maybe it the radiator was not circulating coolant so the temp sensor was constantly reading cold and thus running it rich?

94_f150_ga

Interesting. I would think the sensor would actually be running hot?

If you don't have one, an infrared temp gun are very helpful for tracking cooling issues..they run about $60 or so..

Chris_1

iTrader: (1)

Fuel pressure doesn't sound like the problem. 40 psi is lots. 1 lb per minute is normal bleed off or at least not a serious problem. If it went to 0 in 30 seconds or even 1 or 2 minutes I'd suspect fuel system but yours sounds fine.
Start testing sensors, starting with the TPS