I just reveived my 26# LS1 injectors for my T-Ram intaked IROC and noticed they are about a 1/4" shorter than the set I was replacing. For those that are not familar with a T-ram the fuel rail is cast into the upper plenum. The problem i'm having is thet the injectors do not seat into the fuel rail and intake manifold when the upper plenum is bottemed out against the lower intake. This issue is causing a major fuel leak at the injector. I've heard that the LS1 injectors works with a stock TPI settup. If memory serves me correctly the fuel rail bolts down hard to the intake on a stock TPI so .... how would you use LS1 injectors on a stock settup without millling the lower intake to allow for the shorter injector?

 

You don't have a stock TPI setup...on a stock setup, the injector height can vary and be fine...

I am surprised that you would have bought anything other than stock height injectors...like Accels...given your intake...

 

Honestly I forgot how limited this manifold is with injector lenghts. But in retrospect I didnt think the stock settup had any le-way for diffrent lenght injectors either.

I purchased the current injectors from TPIS about 7 years ago, I dont think they gave me what I asked (payed) for though. The last time my car was on a RW dyno it was running a 15/1 AFR with a wide band o2 @ WOT. BTW suposedly the injectors TPIS sold me were new flow matched BOSCHE 24#rs. Ed Wright burned my chip to match these injectors.

 

actually, the stock setup does have leeway for different injector lengths...hence my comments...the LT1 injectors, SVO injectors and LS1 injectors are shorter and doing a search will show you threads where this has been discussed...

As for TPIS, you should do a search on them as well, there have been a lot of unhappy comments as to their lack of quality/service, especially with their PROMs and occasionally their parts.

That A/F ratio is way too lean...you could up the FP and/or check the PROM and make sure the Injector constant is where it should be...

Do you have scanning software or a scan tool to see what the ECM sees?

 

At the time (94)I didnt know of any other outlet that was flow testing and matching them. What I ordered were new 24# Bosch flow matched, they sent me a set of used injestors that hed diffrent part #s on them. So I learned the hard way about TPIS, wish this site was around at the time!

The 15/1 afr was with afpr cranked all the way down, around 60 psi. The dyno operator couldnt beleive that there was no knocking, the first run was off the chart, over 17/1. At the time there was some 101 octane gas in the tank, probably why it wasnt knocking. I always fill up with 91 octane but when its cool out it still pings.

I do have a scan tool, but I dont think it displays duty cycle. Is there way to calculate duty cycle from the basic sensors that the scan tool displays?

I still plan on using the LS1 injectors, just have to mill about 3/16s" off the bottom of the upper plenum.

 

1994 was a long time ago...so I understand your issue...

As for duty cycle, you can see the pulse width (firing time) of the injectors and there is a formula to calculate duty cycle...unfortunately, I can't remember what it is...but do a search and it should come up...

HTH,

 

if your afpr is screwed down tight it's possable your fuel pump is going south especally if it's stock.i'm running a racetronix kit with the high pressure pump and can hold pressure at 75psi if needed all day big difference over the stock setup

ps i personally wouldent mod a t-ram they are worth too much in factory condition the injecter price for the correst set isent that much
pete
ps did you monitor fuel pressure on the dyno maybe your injectors are alright?

 

Ice Cold

I was monitoring the fuel pressure during every run and it didnt change that much, 2 or 3 PSI. I changed out the stock fuel pump about a year later, no dyno #s, but it dosnt feel any quicker and it still pings.

Your point about not modifying is a good one. I need to find out what it will cost to have the plenum milled in relation to the cost of correct injectors. I really dont feel that bad about modifying an origanel T-RAM, they were designed with compromise in mind. SLP new that the older style injectors were a little shorter so they made the T-Ram work with the older style and added an extra set of gaskets for shimming if you had newer(92) injectors.

 

Well I finally got around to surveying the fuel leak issue. There was one bolt holding the AFPR onto the fuel rail (Upper intake) that was loose, I put it together tonight and it idled normal. I havent driven it yet but I think everything will be fine. I havent road tested it, but the only area I can see a POSSIBLE problem is a small vacumn leak at the injector boss's (vacumn leak). I have an Auto EX-Ray scan tool, If there is a vacumn leak how would I decipher it with a scan tool?