I'm having a low rpm missing/accel surging problem with my 94 Z28 with
135k. I have replaced the opti, plugs and wires. I am now thinking that I have a fuel injector problem. I want to do a balance test.
I have a power supply capable of supplying the proper voltage and current, but won't pulse the injector.
I am worried that the injector cannot take 100% duty cycle long enough to get a pressure reading without frying. Maybe 10 secs would be enough to read the guage.
Am I fooling myself thinking that I can do this without frying the injector?
Will I get a proper reading?
Should I bite the bullet and take it to the mechanic to do this test?
you've replaced the entire optispark, plugs, and wires..... but you haven't replaced your coil pack?? i would definately try replacing your coil pack before you mess with the injectors. MSD and Moroso sells a direct replacement high performance coil for your car. give it a shot.
hmmmmm.... checked the fuel pressure or regulator?? anyways, heres what i would do. i would go ahead and do the test. if you do happen to fry the injectors then you have an excuse to go ahead and buy some bigger injectors like maybe some 28 or 30lb injectors. you can just about find them all day long on ebay for a really good price. or you can swallow your pride and take it to the mechanics shop =( keep us posted.
Damn...beat me to it. Was going to suggest hooking fuel pressure gauge up to shroder valve and checking fuel pressure. (Also might consider compression testing.)
OTC makes a power supply, that pulses at three different rates. I think the cost is 450.00. I'd buy that before toasting the injectors.
The problem would be most likely a leaking injector, not a dead one, because a dead or intermittently firing injector would cause a miss. look towards your fuel pressure bleeding off in a given period of time, like 24 hours, also look at the Throttle Position Sensor as a possibility in your case.
why would you spend $450 on a tool to test the injectors for just a one time use when you can upgrade and replace the injectors for the same price if not and probably cheaper.... just my 2 cents.... oh you know what else, i just remembered this..... in my 95 LT1 Vette i had a proble with it surging one time. it ran like shit and i didn't know what to do. first diagnosis i did was use a paper clip to short out the diagnostics port under the dash and shoot the trouble codes on my dash. OBD1 stands for on board diagnostics 1 so YOU can run a simple diagnostic scan without going to a shop. i had to do a little research on how the papler clip trick worked for my car (probably different for your) but all i had to do was put one end of the paper clip into like hole #4 and the other in #12 or something like that to get my trouble codes to appear on the dash. anyway, it turned out to be a falty coolant temperature sensor. apparrantly, if the coolant sensor is disconnected the car runs like crap. i would look into this as a problem as well. when i was having this problem, the car would jerk like it had a miss from hell... something so simple to cause so much trouble. either get a trouble code reader or find out how to do it yourself with a paperclip. why didn't i think of this before??
Who would pay $450 for a tester? Most Professional repair people. One of my Next major purchases is going to be a used Snap-On MT2500. Probably in the $500 to $700. New they start off around $2000.
My Business Partner has a OBD-1 OTC Pathfinder 2000. You just don't understand what your missing with your paper clip, and flashing SES light. OBD-1 does more then just tell you their is a problem and what circut has it. It will give you read outs from the sensors, as the ECM reads them. The data from it can help you find the problem, instead of making wild guesses as to whats wrong.
But be my guest, keep using your paper clip. Charles
Better known as a pulse tester. As noted they are all over the place. Also, Autozone may rent it for free as part of their tool rental program. Worth a shot.
Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director '80 Carousel Red Turbo T/A, 26k orig. '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going.... '80 T/A project car...
Charles, a guy trying to fix is own car isn't a professional who is going to invest all that cash in equipment. Paying $450 for a tool that is needed 1 time is a waste. And certainly buying a scanner that starts at $2,000 new when you only occasionally work on your own car is equally wasteful. So yeah, for a pro who will get lots of use it's probably a good idea, but clearly that wasn't his situation. Probably a $300 scanning tool is better than a paper clip, but that isn't to say the paper clip thing is completely worthless.
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The test worked somewhat well, but without the pulser, it wasn't necessarily accurate. It did give me a good indication of balance though. Injector On for 1 sec bleeds about 26lbs. All injectors were
+/-1lb from each other. So, I don't think I have an obviously and completely clogged injector. The pulser would have been handy though to give an accurate reading of pph.
Either way, I now think I have a leaking injector. It bleeds off all pressure in about 3 hours.
You know, I happen to own a Ford. A 1985 Ranger 4x4 (2.3-Fuel Injected/5-speed/front lock-outs/15 inch ARE wheels/30x9.50x15 tires. Got her at a dealer auction for $75, including the auction fee. Has a dead fuel pump, and a bad clutch. Destin to live again with a body lift, as well as larger tires, maybe 33x10.50x15's.
My point was any ProWrencher will go out and spend $450 on a tool he/she needs. Further more, if you need something tested and do not have the proper tools. Try to rent or barrow them. If that is not an option, pay someone to test said item for you.
I met a person last year who owns a Snap-On MT2500. This guy does not work on cars for a living. He makes his living off of hauling & installing Hot Tubs/Spa's. His side line work is lawn service for commercial reality companies. He does not make a living from cars, yet he likes working on and around them.
He knows how to use his scanner, and has the portible printer for it. He charges $25 per hour to come to you, Hook up and test. That is pretty cheep. Doesn't matter if your a shop or not. Heck in most cases you couldn't rent a scanner for that, let alone get aquanted with it in one hour if you had not used one before.
Another cheep test some people do is to take a 194 style bulb, and use it as a noid light. Every time I see someone do that, I want to smack them. Noid lights are cheep, like 1/100th of what they used to sell for. I got my set used for $5 bucks, and they are blue point. You can get a new set for under $50, and test GM, Ford, Chrysler & Imports.
For those who do not know, a Noid Light is used to check for injector signal and injector pulse at the wiring connector. It's just to test signals from the ECM.
These days if you work on cars, you have no excuse not to rent, barrow, or purchase the proper tools. If you can not do that, take the car to someone who has them for diagnostic and service. If that is a problem, a for sale sign might be the kinder root for your car. Charles
I use it to beat the shit out of in the winter and have had it for 6 years or more. My friend toasted the clutch last year, when we pulled my motorhome out of the alley, so I could junk it and keep the local police happy.
There's a lot to be said for working with the local police, when you have a bunch of flatulating sphincters for neighbors. The police seem to side with me more!
But anyway, even with the toasted clutch, I plow, I beat the shit out of it, and even when it's 4 quarts low on oil, I never hear a knock!
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