Looking to see if I can get some help with diagnosing. The car ran fine, started right up.Never a problem. I had a break booster go out. And I replaced that. In doing so I had the - the inner left fender and right inner fenders out as I also did the heater core.

got it all?Put back together and she starts immediately but dies.

it's got a new fuel pump in it. By the way, the car set for about eight months as I worked on it, when I could. Got it all back together and she starts and then dies.

i drained the fuel tank thinking it might be bad fuel causing the issue. I use the fuel pump to do so by bypassing the relay. No change

i've tested fuel pressure at the fuel rail. It goes to around 60 immediately and holds to about 56 in 10 min. Interesting thing though if I bypass theRelay pressure jumps to 66.

i have not tested yet at the filter. But plan to do that today.

i have looked over all vacuum hoses. And replaced any that seemed wonky. I even blocked the air going to the new brake booster. Just to see if it was a bad booster, and I got the same results.

security light is not on. It seems functional. For example, it will flash when you open the door. And go off when you close it.

Oh, and if I spray starter fluid, she'll stay running.

 

Testing at the filter. She went to 90+ p s I and then slowly and after ten minutes, she was still around 75.

I redid the test at the schrader valve. This time after ten minutes, she went down to around 50+.. so I guess that means inside I go, i guess it was either going bad or went. Bad while it was sitting while I was fixing the other stuff.

 

Fuel pumps need to be AC Delco or Delphi. If you have 55 psi fuel pressure at the schrader, it wont run but it will run with starter fluid then you have an injector problem. If it starts and then stops a few seconds later with 55 psi then you may have a passlock problem.

George

 

Thanks for the feedback.. Yeah, the fuel pump is definitely a c.Delco I spent the extra money. It holds up good for the leaked out. Test at the filter seventy five p s I after ten minutes.

But I redid the schrader valve test, and it starts off at sixty six, immediately drops to sixty and then subtly bleeds off to around 50 , just above fifty after ten minutes. It was frustrated because. Initially it failed. Then passed. Now it's a consistent fail, three times in a row.. so I should assume I should replace the spider as well s the f p r

 

Well, as I noted, I redid the pressure test leak down tests. At fuel filter it stayed at 75psi after 10 min. at the rail. She does not hold pressure but had got some different readings first go round. Thought it passed, but redid tests and consistently. Bleed down. So I removed plenum.

No washing to show obvious leak. Put fuel lines back in with plenum off . Re did psi test to see where a leak. Starts off at 60psi. Bleeds down two about 40 psi after ten minutes.

Dont see a leak. And Have ordered oem fpr and rebuild kit.

Verified no injectors stuck open. Pressure going somewhere. Can pressure bleed down without visible leaks . I.e inside body of spider?

Also when are poppets supposed to fire? What controls them opening. ICM? As i want to verify them opening WITH Plenum off.I know key on primes system 3 seconds.

 

If your not leaking down at the fuel filter and none of the injectors or plumbing are leaking then it’s the fuel pressure regulator which returns fuel to the tank.

the injectors are fired by the engine computer, There are two ways to test this. The first is with a pulse box or a capable scanner which pulses each injector for a short duration and you measure the pressure loss and compare all cylinders. The second is to use a noid light on the harness for each injector in turn to make sure you are getting pulses. The noid light both indicates firing but also provides the proper load.

George

 

I will give that a go just to check the injectors. Based on all the posts, I assumed that I would see a visible leak. But I will give it a shot. While i'm waiting for the f p r to come in. It is the old style. With poppet valves. CFI.

Thought about upgrading entire spider. But there's so much junk on the internet.I can't tell what's actually real and not a knockoff. She was running fine before so.She just sat for 8 months.

Should injectors shoot gas out when cranking theroricatlly if pressure is within specs with plenum off? Or does that require the hooking all the other connectors.

I understand checking with the light and we'll check the circuit on each. I would assume I would connect to them spotter.Connector to each corresponding set of pins that control each injector. And light should flash during cranking if she's getting the signal. I'd take it any ground would work. I'll have to look at the spotter connector to see if it's marked.I assume it is.

thanks so much for your feedback.

 

Update..

Still waiting on my oem replacement to come. That's what I tested with the noid light all work so she's getting the signal from the computer.

Would you happen to know the ohm specifications for the old poppet injectors as well as the upgraded ones.

 

I believe that the spec is 11-14 ohms, max 3 ohm variation. Not sure if the two generations of injectors are different.

George

 

Thank you for that. Yeah the old all measure about 12.2 .. really no variation between them. The new style measured about 12.5 . doesn't mean they're spraying good, but doesn't look like not much carbon built up at all.

i have the new style only. Because I played around in the junkyard and grabbed a spider out of an 04 S10. I figured I'd practice taking it apart on one that didn't matter, really.

the bracket it was in is smaller, but the body is the exact same. 17091628 as the one that was in my blazer. That's the part number, I guess for the whole spider. Only thing I notice different of course the style of injectors. And the plate that holds them in on the bottom is different.

So is it right when they upgraded the spider?All they did was change the injectors, and the plate and of course, the bracket it fits in.

Anyways, this what I'm getting at? Is it worth the upgrade?