shiner2001

As a brief introduction, I have a 91 Jeep Wrangler with a 4.3 from a 2000 Blazer. This swap was done about 9 years ago and has been great for the most part. Within the last year, I would have a problem starting the Jeep if it had sat for several days to a week without running. At that point, I could crank it until the battery died and not get it to start. However, after an hour or so of sitting (and recharging the battery), it would fire up just fine (and continue to start easily as long as it didn't sit for an extended period of time again). That problem eventually progressed to where it is now, which is that I can't get it start at all. I have fuel to the schrader valve and good pressure as well (it's been a week or so since I checked it, but I believe it was around 35-40 psi). I also have spark. With starter fluid in the tb, the engine will run briefly, so I believe my problem to be somewhere within the fuel injection system. I installed a new fuel pressure regulator and that didn't change anything. What I'm wondering is if the "spider" as I've seen it called, possibly needs to be replaced, as well as if there is anything I can do to test it or each individual injector. I know on my 89 Vette with TPI, I can ohm check each injector, but I am not familiar with working on this CPI system. Any assistance or advice anyone can offer would be greatly appreciated.

As a follow up question, what is the difference in the injector assemblies that are listed as SCPI replacements and the ones that are listed as SCPI to MFI conversions? Is the latter an upgrade and if so, does it install just like the original, or does it require other modifications to be made?

Thanks in advance!
--Derek

72c10gunn

Im not real great with FI but i think your pressure is lower than it should be, I remember readin that maxxman did the scpi to mfi conversion on his tahoe maybe he can elaborate on what the swap is and what psi you should be looking for.