3800 Injector Question

[RynosGP]

I just a-tapped my car today and I notice that my injector pulse width is up from the last time. I figured it would go up a little since I added SLP Headers 180T-stat, 3.4 pulley, and DHP PCM. But it just seems that it went up too much. My car has 160,000 miles on it. When I'm at WOT the Injector pulse width is at like 22 and the hightest is at 23.6. For some reason i was thinking the value for a static injector was like 23 or 24 or something like that. Eveything else on the a-tap looked normal. I just want to know if my injectors are ok. Plus it idles rough and surges with it first starts up. Any help would be great. Thanks, If you need me to post my a-tap file I can do that. Againg, thanks for you help.

Thanks,

Ryan

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[imported_Ron Vogel]

Sounds like your EGR is sucking in air, or the pintle may be stuck with carbon deposits.

 

[sweetness]

also remember that headers are going to cause your car to lean out. (better flow)Your injectors have to work harder to supply that fuel, thats why you saw the increase. Might want to get them cleaned though. Thats probably all you need.

BC

 

[imported_Ron Vogel]

Originally posted by sweetness@Feb 21 2004, 02:32 PM
also remember that headers are going to cause your car to lean out. (better flow)Your injectors have to work harder to supply that fuel, thats why you saw the increase. Might want to get them cleaned though. Thats probably all you need.

BC

This is the thing that sucks about the linear EGR we have. When you do any exhaust work, or increase the flow into the motor it makes it impossible to tune. The EGR has a flow measurement in side it that measures delta pressure from the exhaust and the intake. Any exhaust work or pulley changes can make drastic tuning differences because of manifold or exhaust pressures that are different than stock. The EGR table are made to work ridigly with the stock compenents. That's why a lot of people will disable it. I agree the injectors need to be cleaned, but as the computer readjusts to the headers the EGR table stays the same and will cause some tuning issues.

 

[sweetness]

so getting rid of the egr is just a good idea. Especially if you have to get the car tuned??

BC

 

[RynosGP]

Thanks for your help. I never thought to look at the EGR. I'll check that out and see if that helps.

Thanks,

Ryan

 

[imported_Ron Vogel]

Originally posted by sweetness@Feb 21 2004, 04:37 PM
so getting rid of the egr is just a good idea. Especially if you have to get the car tuned??

BC

Kind of, if you really want to tune the car it's the thing to do. Since I'm working on an EGR spoof right now I did some research on it and came to this conclusion. The egr tables should be updated for performance mods, but that's not really practical since a lot of time and effort goes into providing the EGR tables that go into a stock car. There are huge reseach papers out there on the subject.

 

[rob]

Ron, is it possible to try an artificially replicate the pressure to the EGR. Maybe closing up the hole in the header a little will help get the pressure up. Or is volume a factor too. Please let us in on your conclusions.

 

[imported_Ron Vogel]

Actually haven't tried it, but if the side of the egr going to the intake was routed to before the maf it should pull enough vaccum to prevent throwing a code.

 

[JEFFSGTP]

^^^^^ THAT IS A VERY INTERESTING IDEA i MIGHT HAVE TO TRY THAT, BECAUSE i KNOW MY BLOCK OFF PLATE IS SCREWING WITH MY LTFT'S Also VOLUME is monitored by the egr. when I first put the block off plate on I mearly taped a crank case vent filter on to the tube and I threw an EGR insufficient flow code at least I knew the tape was holding its seal properly

 

[RynosGP]

I was just doing a little reading and found that it could be a problem with the fuel pump. I forgot to say that I got my Injectors cleaned with they GM process that they just run the car off of the cleaner about 6,000 miles ago. Not sure if that process is anygood or not. Also just doing some reading about the fuel pump problem. How long do most fuel pumps last? Mine has never been replaced and has 160,000 on it. Could it just be worn out?

Thanks,

Ryan

 

[rob]

Check the fuel pressure: 44-55psi....

 

[RynosGP]

Thanks rob. I've been looking for what the fuel pressure is suppposed to be for like an hour. I couldn't find it anywhere. I'll check it tonight and see where it's at. So if the pressure is below that is it a safe bet to say the the pump is either going bad or possibly the Fuel filter. I think I've only put about 10,000 miles on this fuel filter.

 

[rob]

I forgot to ask what year your car was. That pressure I gave you was from the GM 2000 W-service manual...Let me double check or you can just call your GM service dept-they will tell you-even a auto parts store will tell you stuff like this-provided its correct...I always call the dealer when I cant find a stat-for the future.

Should be the same though...Yes 97-00 is 48-55 vin 1 SC

 

[RynosGP]

Well I just checked my fuel pressure and when I started it up in idle the pressure what 54 psi. Then I checked the pressure with the vacume line off and plugged and the pressure went up to 60 psi. It just seems a little high to me. I woud assume that my fuel pump is still good since the pressure is up and also the filter. But I don't think that the injectors being clogged would cause the fuel pressure to rise since it's a returnable fuel system. I could be way off. Any thoughts on this?

Thanks,

Ryan

 

[Scott P]

I just had a set of injectors cleaned through www.cleaninjectors.com and should be installing them instead of posting here. We got four guys together to get them cleaned and got a little group discount. One set had bad return springs and almost weren't useable. So, yes. Injectors do wear out.

 

[RynosGP]

Thanks. I guess they could wear out but I wasn't sure how long they usually last. My main concern is that my IPW are at 22 up to 23.6 at like 5700 RPM. That would be going static right? Also my fuel pressure being at 54 psi @ idle and 60psi with the vacume line off and plugged. Anyone else have anythoughts to what the problem might be?

Thanks,

Ryan