sfpar Posted May 25, 2007 Author Share Posted May 25, 2007 Sounds like you have a MAJOR air leak somewhere, like in the MAP sensor circuit (hoses, not electrical)... Where are you tapping into the intake manifold for the MAP connection? As I am racking my brain for possible culprits would it possibly have anything to do with a BOV I installed. I don't really hear leaks but it is one place that could be allowing extra air into the intake side. Just a thought. Scott Quote Link to comment Share on other sites More sharing options...
Warren Posted May 25, 2007 Share Posted May 25, 2007 Scott, Without knowing which wastegate and BOV you're running and how you have the vacuum lines routed to both the turbo, wastegate and BOV, it's almost impossible to tell from here. I do know that some wastegates use different ports for vacuum and pressure. Also, If you're using a boost controller, it could be that one of the lines on it are not hooked up correctly as well. I hate picking straws, but that's all I can think of at the moment. Need more specifics on hardware and how the vacuum lines are run to be of any more help at this point. Quote Link to comment Share on other sites More sharing options...
sfpar Posted May 25, 2007 Author Share Posted May 25, 2007 Tomorrow, I'm going to slap my old injectors in and see how it runs. I know those worked before and it's worth a shot. Thanks guys. I'll let you know how it works out. Scott Quote Link to comment Share on other sites More sharing options...
sfpar Posted May 27, 2007 Author Share Posted May 27, 2007 COuld it be possible that SDS sent me the injector harness for a High impedence injector? If you have low impedance injectors, you should NOT have the resistor pack inline... If you told Racetech that you were using low impedance injectors, they should not have put it in the harness before sending it to you. I have it barely running at 250 the max. Sounds like you have a MAJOR air leak somewhere, like in the MAP sensor circuit (hoses, not electrical)... Where are you tapping into the intake manifold for the MAP connection? I went to my buddy's shop saturday, where the car is, to try a few things out. Warren first of all, I checked out the injector harness and I definitely have the resistor pack on the harness and it looks exactly like the image you posted. Sorry for the misinformation before. Could this be causing my problems? According to the above post it sounds like I should not have this resistor pack with my Low Imp. injectors, correct? Second, the BOV is not leaking any air and is functioning properly as far as I can tell. Third, on Saturday, I put the old fuel rail with my old N/A injectors in just to see what would happen. It ran the same as with the 450cc injectors. No difference at all. As a matter of fact, when the car warmed up it wouldn't start or run. I was able to start the car two different ways. First, by spraying starting fluid in the intake. Second, when I would take the ground off the injector harness and repetitively tap it on and off the car frame I could manipulate the opening of the injectors to keep it running, poorly, but running. I am sending unit back to Racetech for examination on Tuesday. Something tells me that the injectors are not receiving the signal from the computer to open/close properly. All other parameters read correctly on the hand held tuner. ie. Man press., RPM's, ET, AT, etc. That being said, the computer is receiving proper information but not sending it. I hope this is what Racetech finds when they check the box. Thanks for your help. Scott Quote Link to comment Share on other sites More sharing options...
Warren Posted May 27, 2007 Share Posted May 27, 2007 OOPS, My bad, I apologize, profusely... I just re-read what I typed...For the LOW impedance injectors you SHOULD definitely have the resistor pack inline. This will cause your injectors NOT to fire should you be using low impedance injectors without the resistor pack. I had edited that original post a couple of times and typed it wrong in the process. The injector pack is for use with low impedance injectors and therefore SHOULD be inline. (I went back and edited the original post containing the picture above.) Sorry for the confusion. Now, since you can get it to run with spraying starting fluid, you're definitely getting spark, so rule that out. Perhaps you're not getting fuel pressure because the fuel pump is not coming on. When you turn the key to the on position, you should hear the fuel pump come on for about 4-5 seconds to pressurize the fuel rail. Does it come on? Can you hear it while sitting in the car, before you even crank the car over? One other thing to remember is that the injectors should see 12V all the time (when the key is on), as the SDS ECU provides a GROUND signal pulse...be sure you have the injectors seeing 12V when the key is on. Warren Quote Link to comment Share on other sites More sharing options...
Clifton Posted May 27, 2007 Share Posted May 27, 2007 Maybe I missed it in here, but what fuel pressure are you running? I assume you are running an after market FPR with that fuel rail. Also for the future. A leaking BOV won't effect the signal on a map based system and a vacuum leak would just bump up your idle speed. Quote Link to comment Share on other sites More sharing options...
sfpar Posted May 28, 2007 Author Share Posted May 28, 2007 Thanks for clearing that up and hanging in there with me. Regarding the fuel pump. On a 78 my pump runs while cranking and then continuously after the start. I have checked it out and it is working properly. I even hooked a small 12v motorcycle batt directly to it just to make sure and no difference. We have checked voltage on the injectors and it is 12v with key on. Now, when cranking it does drop to 10 but then comes back up to 12 after start. You are correct Clifton. I am running an after market adjustable FPR that I purchased on Ebay. I have tried it at 38lbs and even cranked up the pressure to 55lbs. with no difference. I'm sorry I can't remember the make of the FPR as I purchased quite a while ago. I do have a pressure gage. I'm actually thinking of putting the AFM and old ecu back in. How bad is that? Quote Link to comment Share on other sites More sharing options...
sfpar Posted June 1, 2007 Author Share Posted June 1, 2007 Hey Gents. Racetech called and said my computer is working fine and the injector I sent them is good as well. So much for that theory. Now they want me to see how much fuel is drained from the return fuel line in one minuetes time. I do have an aftermarket el cheapo adj. FPR from ebay. It looks good but maybe it is the problem. Here is the link to what I purchased. http://cgi.ebay.com/ebaymotors/UNIVERSAL-FUEL-PRESSURE-REGULATOR_W0QQcmdZViewItemQQcategoryZ33742QQihZ020QQitemZ300115163076QQrdZ1 Any other suggestions?? Thanks. Scott Quote Link to comment Share on other sites More sharing options...
Warren Posted June 1, 2007 Share Posted June 1, 2007 If you open up that regulator, you'll find out that the orifices inside are TINY... I had an issue with one of those at one time that proved to be a MAJOR problem. It wouldn't flow enough fuel to keep the motor running and it leaked like a sive. Invest in a decent FPR or revert back to the stock one (which will be sufficient for what you need, as Racetech tell ya to begin with). I now use an SPX adjustable regulator and have not had ANY issues with fuel since. Glad to know your ECU and injector is functioning properly though...that's good news. Warren Quote Link to comment Share on other sites More sharing options...
sfpar Posted June 1, 2007 Author Share Posted June 1, 2007 If you open up that regulator, you'll find out that the orifices inside are TINY... I had an issue with one of those at one time that proved to be a MAJOR problem. It wouldn't flow enough fuel to keep the motor running and it leaked like a sive. Invest in a decent FPR or revert back to the stock one (which will be sufficient for what you need, as Racetech tell ya to begin with). I now use an SPX adjustable regulator and have not had ANY issues with fuel since. Glad to know your ECU and injector is functioning properly though...that's good news. Warren Thanks Warren. I will try another reputable FPR and go from there. Scott Quote Link to comment Share on other sites More sharing options...
Clifton Posted June 1, 2007 Share Posted June 1, 2007 I've seen the orifice on those. It was a little larger than my 7M one but still on the small side. A regulator not returning enough fuel will just cause the pressure to rise though. If your pressure is good, it's good. I would try another pressure gauge to check your fuel pressure if you question it. You do have it hooked up right, right? Quote Link to comment Share on other sites More sharing options...
sfpar Posted June 1, 2007 Author Share Posted June 1, 2007 I've seen the orifice on those. It was a little larger than my 7M one but still on the small side. A regulator not returning enough fuel will just cause the pressure to rise though. If your pressure is good, it's good. I would try another pressure gauge to check your fuel pressure if you question it. You do have it hooked up right, right? Yep, It's hooked up correctly. The directions were simple enough that even I couldn't mess it up. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.