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New to forum but wanted to share my recent injector swap out. 1992 C4 LT1 had 5 original and 3 replaced somewhere along the line. Engine had rough idle and a miss that would come and go. Installed a set of 30 psi accel injectors along with a fuel filter. Turns out the filter was a little trickier than injector swap. Fired it up and computer picked up the change to higher psi injectors quickly. Runs rock solid and the power difference is a nice bonus. It has never run this well. Sweetness!
Spent about $350 for injectors and filter. YouTube video on swap out was priceless.
If your running a stock engine, the 30's may be too much for your set up. Stock is 22 pound injectors. The computer will compensate for a change, but his might be too much.
Nothing wrong with the Accel's. Have run them for years on my 85 and then changed out the originals on the 95.
Fired it up and computer picked up the change to higher psi injectors quickly. Runs rock solid and the power difference is a nice bonus. It has never run this well. Sweetness!
I thought it was rated at pph (Pounds Per Hour)? PSI is pressure and should be around 43.5? Maybe it has never run that well because your 5 or maybe even 8 were clogged. I'm not sure what the effects of a 30pph injector swap are when you are rated 24. That is a 25% change. Anyone know if the ECM is capable of that much adjustment?
Thanks for the tip Ant. I did pull up and swap filter on bench. Getting it up on stands, wheel off, brackets off, and lower filter nut very tight on me. Also pulled fuel lines at gas cap to break siphon. Youtube video very helpful on filter swap.
Pounds Per Hour sounds like the correct terminology thanks for updating me Aklim. I was concerned with the jump but couldn't find anything concrete on forum so eventually just went with the swap. Next smog test is two years away and I may need to look at ECM at that time. As well as it runs I have hopes it will slide on through. A noticeable power increase since swap, however it was running poorly prior to the change. Thanks for input!
I had basically the same problem with my 89 when I bought it, a horrible miss at idle and cruise but no issue when floored. I replaced all my injectors with new 22lb Accels and lost considerable power when I did.
So 22lb Accels are not equivalent to what the factory put in it. Next time I have to tear into the top end those Accels are coming out.
I do remember asking for advice on putting larger injectors in before I did the work but most stated that unless I'm upgrading the electronics to compensate for the extra gas it would be a waste.
I had basically the same problem with my 89 when I bought it, a horrible miss at idle and cruise but no issue when floored. I replaced all my injectors with new 22lb Accels and lost considerable power when I did.
So 22lb Accels are not equivalent to what the factory put in it. Next time I have to tear into the top end those Accels are coming out.
I do remember asking for advice on putting larger injectors in before I did the work but most stated that unless I'm upgrading the electronics to compensate for the extra gas it would be a waste.
Rick
You need to see if you have 22pph at 43.5 psi fuel pressure to compare.
I suspect that they weren't working right assuming everything else is ok.
Why people don't tear out the injectors every few years for cleaning and testing, I don't know.
Yes the ECM will compensate till it can't. After which it will not run right. Extra gas will only make it run rich and if it can't burn the fuel, I am not sure what the point would be.
The Accel 30 PPH injectors seem to be a pretty safe bump for my application. ECM handled the change within two minutes. That doesn't mean the other emission components won't give problems down the road but as tight as this thing runs now I feel satisfied. Once I get it on the sniffer I will know for sure. NOx has always been borderline on this vehicle. High NOx levels are seen when things are lean... I will post next smog test when i run it. This picture was test prior to swap.
You need to see if you have 22pph at 43.5 psi fuel pressure to compare.
I suspect that they weren't working right assuming everything else is ok.
Why people don't tear out the injectors every few years for cleaning and testing, I don't know.
Yes the ECM will compensate till it can't. After which it will not run right. Extra gas will only make it run rich and if it can't burn the fuel, I am not sure what the point would be.
Don't quite follow you here, are you saying all 8 new injectors are not working properly?
The car now runs, cruises, idles and accelerates smooth as silk, it just doesn't have the floorboard power it had with the old ones.
To test them I would have to take them out, if I do that they're not going back in even if they are working as they're supposed to.
I have also replaced everything fuel related except the actual fuel lines and tank.
The ecm controls the ontime in milliseconds to the injectors.If you give a 8 ms pulse on a 30lb/hr injector you should get more fuel than a 22lb/hr on the same pulse.What the members are questioning is why is the car not running rich?My guess would be a weak fuel pump.I have a snap-on fuel pressure gauge the I tape to the windshield and go for a test drive.If the pressure stays at 38-40 psi under load the pump/fuel filter are good to go.As for the high NOx usually the egr system is to blame.But the ecm might not be programmed to trigger the egr at the test conditions that California uses.If you tee a vacuem gauge onto the vacuem line at the egr valve and drive the car you can check to see if the valve is getting a vacuem signal to open.If you apply vacuem to the egr valve while the car is idling the engine should run rough or stall.I used to have a smog tech license in California.
Don't quite follow you here, are you saying all 8 new injectors are not working properly?
The car now runs, cruises, idles and accelerates smooth as silk, it just doesn't have the floorboard power it had with the old ones.
To test them I would have to take them out, if I do that they're not going back in even if they are working as they're supposed to.
I have also replaced everything fuel related except the actual fuel lines and tank.
Rick
Sometimes the message can get muddled through different posts. The simple message is The Accel 150830 Fuel Injector set of eight matched injectors swapped out perfectly for the stock injectors. The ECM adjusted for the higher fuel flow fairly quickly and the vehicle is not running rich. Car now runs very solid, idle is smooth and acceleration or "floorboard power" is better than it has ever been.
Fuel pressure is good and the EGR system is functioning correctly. If anyone has a question feel free to drop me a note!
Sometimes the message can get muddled through different posts. The simple message is The Accel 150830 Fuel Injector set of eight matched injectors swapped out perfectly for the stock injectors. The ECM adjusted for the higher fuel flow fairly quickly and the vehicle is not running rich. Car now runs very solid, idle is smooth and acceleration or "floorboard power" is better than it has ever been.
Fuel pressure is good and the EGR system is functioning correctly. If anyone has a question feel free to drop me a note!
Cheers
Question is why it can make such a quick adjustment
Leaves me wondering also how the computer could compensate for such a large change in injectors.
But I guess the bottom line is that it is working for him. If it is working, why fight it.
Under certain circumstances it might be able to compensate I suspect. Besides SOTP feeling is so subjective I would hardly trust it personally. You ever not see the kids tell you how fast the car feels because they tossed money at it without proper verification?
Maybe because almost every too good to be true" situation usually plays out thst way in the end?
aklim, we both have this "gut feel" that this is not right. The only way to be sure would be the sniffer in the tail pipe. Or if that is not available, read the plugs after driving it for awhile. SOTP, like you say is subjective.
But he does indicate that it is running better and stronger. At WOT?? or casual driving down the road? Guess that at WOT it might be good, but would eventually load up running rich just casually driving down the road.
aklim, we both have this "gut feel" that this is not right. The only way to be sure would be the sniffer in the tail pipe. Or if that is not available, read the plugs after driving it for awhile. SOTP, like you say is subjective.
But he does indicate that it is running better and stronger. At WOT?? or casual driving down the road? Guess that at WOT it might be good, but would eventually load up running rich just casually driving down the road.
Driving time will tell.
Not sure. Can you read plugs in an FI vehicle? Before I got rid of my carbed toys for FI (Seadoos and ATVs), they said the way was to put a fresh set of plugs, do a WOT run, pull and read. But if FI keeps adjusting it, is the read indicative of much? Besides, if you know it runs rich or lean at one point of a curve, what are you going to do about it? Not kike you can change the jets on a carbed motor. Maybe the better thing is to change the fuel injector constant in the chip?
aklim, we both have this "gut feel" that this is not right. The only way to be sure would be the sniffer in the tail pipe. Or if that is not available, read the plugs after driving it for awhile. SOTP, like you say is subjective.
But he does indicate that it is running better and stronger. At WOT?? or casual driving down the road? Guess that at WOT it might be good, but would eventually load up running rich just casually driving down the road.
Driving time will tell.
Good point regarding loading up over time under normal driving conditions. It has a little over 200 miles on it since the swap and tail pipes appear clean and no noticeable odors when idling for extended periods. When I get the chance I'm going to run it over to smog test center and see how things look, you guys are making me nervous . Next test isn't due for two years but if I need to make adjustments I don't want to wait till last minute. Are there modifications available for ECM or would adjusting fuel pressure as Boot77 mentioned be a better choice? Thanks for all the input it is sincerely appreciated.
Accel 150830 Fuel Injector
. Next test isn't due for two years but if I need to make adjustments I don't want to wait till last minute. Are there modifications available for ECM or would adjusting fuel pressure as Boot77 mentioned be a better choice? Thanks for all the input it is sincerely appreciated.