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Installed new injectors on 90 TBI, now it won't start.

Jessie James

Jessie James

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I just swapped in new injectors into my 1990 350, along with a new fuel pressure regulator & spring, new o-rings, a new fuel filter, new cap & rotor, new plugs & wires, and a new battery. Now when I try to start it, I turn on the key, hear the fuel pump charge, it turns over fast and smooth, and will start with starting fluid. However, it dies after a few seconds.

I checked for vacuum leaks and found one line loose on the ball-shaped reservoir near the drivers side firewall so I pushed that back on, and checked all other lines and everything seems to be in order. I've checked all wires that I can see to the various modules on top of the block, and they all look fine.

I've been driving it just fine prior to this.

Any suggestions on what to pull apart and check? I am thinking the fuel pump may not be delivering enough fuel through the new regulator, but I'd like to know if there is anything else simple/obvious I can check before I start pulling the fuel lines off. :)
 
check for spark.

check all fuses under dash left side firewall.

pump might run but is it building psi? tbi runs around 12-15 for who you talk to.

and it might be the since you worked on it now its broke problem.

and i had a ignition module go on me crank but no fire.

have someone crank it and watch for spray from injectors.
 
sweetk30 said:
check for spark.
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I am assuming I have spark since it will run for 3-5 seconds with starting fluid.

sweetk30 said:
check all fuses under dash left side firewall.
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Any one in particular?

sweetk30 said:
pump might run but is it building psi? tbi runs around 12-15 for who you talk to.
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That's the question, and I don't have a fuel pressure tester.

sweetk30 said:
and it might be the since you worked on it now its broke problem.
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I hate that but you're probably right. :)

sweetk30 said:
and i had a ignition module go on me crank but no fire.

have someone crank it and watch for spray from injectors.
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Good idea, I will do that.
 
Might sound silly but, you did reconnect the injector wires? Also make sure they haven't become pinched between the TBI and air cleaner (a PO had pinched mine at some point as you can see where the wires have been pinched).
 
I did check those, unplugged them and put them back on to be sure. And I looked to be sure they were not pinched, and followed them back through the loom as far as I could to be sure nothing was caught.

I ordered a shop manual about two weeks ago in preperation for this project, and it still has not arrived. :mad:

This sucks. The last day I worked on this it was sunny and nice. Now every day has been rainy and cold. I just want it to start dangit! :draw:
 
Chaddy said:
Unhook the fuel filter and crank it over to see if fuel shoots out.
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I am thinking my fuel pump is not giving enough pressure or the injectors are not getting power. I had fuel the day before I put the new parts in and the truck was running fine, so this is frustrating. Not to mention i found a pinhole leak in the fuel line after I replaced the filter, so I had to fix that too.

I've climbed over that engine at least 6 times looking for anything that may have been unplugged or knocked loose. I'll check in a while and update you all.
 
Did you check the tire pressure?:D jk


Sorry, if it runs with spray can it has to be in the delivery system(connectors, fuel lines, filters).
 
Oh it needs new tires too. And a new catalytic converter and a new exhaust. Among other things. :D

So yeah, I think it has to be fuel since it has spark and compression and runs on the fluid... now why won't the sun come out???
 
If you've checked the injector wiring i would now pull the injector pod back off and recheck that the fuel regulator is put together correctly. It is pretty common for the diaphram to move on you and cause it to not build pressure and then it won't start.
 
4X4HIGH said:
If you've checked the injector wiring i would now pull the injector pod back off and recheck that the fuel regulator is put together correctly. It is pretty common for the diaphram to move on you and cause it to not build pressure and then it won't start.
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That sounds likely. How do I put that together to avoid this issue? I just put the spring in, put the diaphragm in, and then slowly screwed it down by rotating through the screws and doing 1-2 turns each.
 
Jessie James said:
That sounds likely. How do I put that together to avoid this issue? I just put the spring in, put the diaphragm in, and then slowly screwed it down by rotating through the screws and doing 1-2 turns each.
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The diaphram goes against the injector pod first, then the spring sits on top of it and then the cover goes over the spring and you have to compress the cover/spring while not allowing the corners of the diaphram to lift up and squeeze in while tightening the cover screws.
 
4X4HIGH said:
The diaphram goes against the injector pod first, then the spring sits on top of it and then the cover goes over the spring and you have to compress the cover/spring while not allowing the corners of the diaphram to lift up and squeeze in while tightening the cover screws.
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Sounds like you need to do some praying as well!!
 
4X4HIGH said:
The diaphram goes against the injector pod first, then the spring sits on top of it and then the cover goes over the spring and you have to compress the cover/spring while not allowing the corners of the diaphram to lift up and squeeze in while tightening the cover screws.
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Oh, see, I did this backwards. I put the spring in first. Okay, I'll re-do that and see what happens.
 
Jessie James said:
Oh, see, I did this backwards. I put the spring in first. Okay, I'll re-do that and see what happens.
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That is definately your problem, instead of the spring holding the diaphram against it's seat it is holding it away and not allowing pressure to build up thus the no fuel spray.
 
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