92Red454SS
Newbie
Here’s the install and the pressure
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92 454SS Hard Start stalls fuel pump runs continuously
- Thread starter 92Red454SS
- Start date
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What kind of a distributor do you have? Is it a Delco? Have you changed the ICM (with a Delco) recently? It seems to be a common issue with these TBI setups.
https://www.summitracing.com/parts/ado-d1984a
https://www.summitracing.com/parts/ado-d1984a
92Red454SS
Newbie
It’s all original. Today was the first time the air cleaner base was removed..
I have not changed the ICM. I suspected that but read where others have changed it with no change in starting. As it hasn’t been stalling after start lately, I wasn’t looking at the ICM.
I have not changed the ICM. I suspected that but read where others have changed it with no change in starting. As it hasn’t been stalling after start lately, I wasn’t looking at the ICM.
someotherguy
Truly Awesome
Yeah, to get it installed behind the TBI you generally have to loosen/remove the fuel line clamp attached down behind the engine at the top of the transmission, so that you can adjust the line position to allow for the adapter. That was my experience on the small block; figured the big block is similar.
Your pressure seems good but I wonder if the pump is working overtime to build it due to cracked/pinholed fuel line at the sender? It happens once that line gets old since the fuel is constantly attacking it. I wouldn't suggest going to the hassle of dropping the tank or lifting the bed just to check, but you might end up there anyway. A fairly easy test would be to very briefly deadhead the pump and see how much the pressure spikes. Unfortunately I don't have hard numbers on what to expect, but if it changes starting behavior immediately, you may have found the issue.
I do the deadhead test by carefully clamping a thick piece of plastic folded over the rubber section of the return line. You don't want to go nuts and damage the line. Clamp it off and watch the gauge as you start the engine, then shut it right off.
Fuel pressure regulator inside the TBI may be getting weak, or that line from pump to sender may be the suspect. Again I'm not saying you should immediately go into the tank, but it's a possibility.
FAIR WARNING this test may possibly find the weak component and send it over the edge, so you may not want to do it right now if you're depending on the truck for transportation.
BTW this is what years of sitting does to that line
this is obviously a very extreme example, but is a reminder of how harsh an environment inside the tank is. The fuel has very clearly gone super bad and turned the line to jelly... but in far less extreme examples it causes cracks and pinholes in the line and makes it hard for the pump to build sufficient pressure to start. I had one where that exact issue caused long crank times before starting.
Richard
Your pressure seems good but I wonder if the pump is working overtime to build it due to cracked/pinholed fuel line at the sender? It happens once that line gets old since the fuel is constantly attacking it. I wouldn't suggest going to the hassle of dropping the tank or lifting the bed just to check, but you might end up there anyway. A fairly easy test would be to very briefly deadhead the pump and see how much the pressure spikes. Unfortunately I don't have hard numbers on what to expect, but if it changes starting behavior immediately, you may have found the issue.
I do the deadhead test by carefully clamping a thick piece of plastic folded over the rubber section of the return line. You don't want to go nuts and damage the line. Clamp it off and watch the gauge as you start the engine, then shut it right off.
Fuel pressure regulator inside the TBI may be getting weak, or that line from pump to sender may be the suspect. Again I'm not saying you should immediately go into the tank, but it's a possibility.
FAIR WARNING this test may possibly find the weak component and send it over the edge, so you may not want to do it right now if you're depending on the truck for transportation.
BTW this is what years of sitting does to that line
this is obviously a very extreme example, but is a reminder of how harsh an environment inside the tank is. The fuel has very clearly gone super bad and turned the line to jelly... but in far less extreme examples it causes cracks and pinholes in the line and makes it hard for the pump to build sufficient pressure to start. I had one where that exact issue caused long crank times before starting.
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Richard
92Red454SS
Newbie
It’s been over ten years since I replaced the fuel pump and was anxious to see my pressure readings figuring I would see a pressure problem. I don’t know. It is not my daily driver..
DerekTheGreat
Forum Regular
Ooo I have nothing relevant to say about your issue now but I love that cluster. I wonder how much one of those would go for on fleabay...
92Red454SS
Newbie
Any thoughts on FRP or injectors? I've searched the forum and have not come up with any relevant discussion.. My TB has never been apart.
At what point in time did you connect a scan tool, to inspect the data stream for anomolies?
What is the system voltage WHILE CRANKING?
What is the amount of cranking vacuum?
What is the cranking compression of all eight?
Do you have spark while cranking?
Do the injectors spray fuel while cranking?
What is the system voltage WHILE CRANKING?
What is the amount of cranking vacuum?
What is the cranking compression of all eight?
Do you have spark while cranking?
Do the injectors spray fuel while cranking?
92Red454SS
Newbie
Up until about 10 minutes ago I hadn't scanned for data. No check engine light to prompt me (ignorant). It scanned codes 42 (ICM), and 54 (fuel pump circuit-voltage low. I reset the codes and scanned again. Codes were cleared. Restarted the truck and then re-scanned again. No codes present.
System cranking voltage WHILE CRANKING:
xc_hide_links_from_guests_guests_error_hide_media
Cranking vacuum: Haven't check yet.
Cranking compression: Engine runs strong once started. No complaint of power or performance. Can I assume compression is good?
It starts while I crank so I have spark while cranking.
The injectors begin to spray fuel when I begin to crank.
92Red454SS
Newbie
I ordered the D1943a. Same as the D1984a? They both show appropriate for the application.
