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I have an 88 camaro, 305tbi. I'm stumped. It ran great for a couple days after I replaced the egr solenoid and fuel filter. Then decided to take it out on the highway for the first time and it started surging when accelerating past 1/4 throttle or so. Exhaust smells rich. It's got a new coolant temp sensor, I tried swapping map sensor with a known good one, took the plug wires off my pickup that runs great, cap and rotor are new when I got the car a couple weeks ago. I put another new fuel filter on, but it's rich so I don't see that being the problem. Injectors seem to have a good Spray pattern. Nothing changes this issue. Also tried capping off egr vacuum line. It's got like 22"hg of vacuum at idle in park also. I'm very quickly running out of ideas here. Idles good and revs up great in park too.
Re: 305tbi surges when accelerating. Runs really rich
Originally Posted by Purplestaff
I have an 88 camaro, 305tbi. I'm stumped. It ran great for a couple days after I replaced the egr solenoid and fuel filter. Then decided to take it out on the highway for the first time and it started surging when accelerating past 1/4 throttle or so. Exhaust smells rich. It's got a new coolant temp sensor, I tried swapping map sensor with a known good one, took the plug wires off my pickup that runs great, cap and rotor are new when I got the car a couple weeks ago. I put another new fuel filter on, but it's rich so I don't see that being the problem. Injectors seem to have a good Spray pattern. Nothing changes this issue. Also tried capping off egr vacuum line. It's got like 22"hg of vacuum at idle in park also. I'm very quickly running out of ideas here. Idles good and revs up great in park too.
Goodmorning purple staff, I literally joined ThirdGen last night and I posted nearly the same Issue with my Trans am last night. I have the factory service manual and I’ve booked marked several different sections of the book, I have additional problems with power and sometimes a long start. I haven’t changed the fuel filter yet, I was actually glad that you mentioned that you replaced the filter and saw a change, it’s something I wanted to do today but I want to run my tests first before any money is spent. What ever I learn from my tests I’ll pass the information along in my post, maybe it will help you with the surging issue, mine does that too EXACTLY how you describe, but only intermittent.
I also have a 88’ GTA TPI I bought when I was 17, and that is a 305 TPI with the 5 Speed Manual . I had the terrible exhaust odor in my 88’ and after going crazy, and wasting ALOT of money due to inexperience I finallyfound that it had an aftermarket “ CJET” performance chip in the Ecm. I took it out, and put the original Prom in, and the Surging, rough running, heavy exhaust smell was completely gone and the car ran so beautiful, the idle was smooth as glass and there was no Odors of heavy exhaust fumes. Maybe you have a chip like my 88’ did.
to be safe, I didn’t know what was done to my 88’, meaning I was the 7th + owner of the car who knows what the previous owner did, update cams, injectors etc. so I found a guy who programmed chips out of his house in Georgia, I Emailed him explaining my situation and I sent the chip to him so he could tell me what the chip was for. He told me that the chip had programming in it to change the fuel values, delete the RPM redline, and other little performance tweaks.
I gave him the “ blueprints” to what I wanted to modify, which included cam, injectors, heads, ported TPI , coolant temp values and the deletion of VATS. He reprogrammed everything to the specs and the specs were inline with the mechanical upgrades and everything else I did. It was a total success. I never had any issues ever again. I’m not saying this is your problem, but my issue was a bad aftermarket chip and slapped on aftermarket parts that weren’t inline with the chips programming. Causing all kinds of problems . Hope this helps
Re: 305tbi surges when accelerating. Runs really rich
Originally Posted by Syo1989Ta
Goodmorning purple staff, I literally joined ThirdGen last night and I posted nearly the same Issue with my Trans am last night. I have the factory service manual and I’ve booked marked several different sections of the book, I have additional problems with power and sometimes a long start. I haven’t changed the fuel filter yet, I was actually glad that you mentioned that you replaced the filter and saw a change, it’s something I wanted to do today but I want to run my tests first before any money is spent. What ever I learn from my tests I’ll pass the information along in my post, maybe it will help you with the surging issue, mine does that too EXACTLY how you describe, but only intermittent.
I also have a 88’ GTA TPI I bought when I was 17, and that is a 305 TPI with the 5 Speed Manual . I had the terrible exhaust odor in my 88’ and after going crazy, and wasting ALOT of money due to inexperience I finallyfound that it had an aftermarket “ CJET” performance chip in the Ecm. I took it out, and put the original Prom in, and the Surging, rough running, heavy exhaust smell was completely gone and the car ran so beautiful, the idle was smooth as glass and there was no Odors of heavy exhaust fumes. Maybe you have a chip like my 88’ did.
to be safe, I didn’t know what was done to my 88’, meaning I was the 7th + owner of the car who knows what the previous owner did, update cams, injectors etc. so I found a guy who programmed chips out of his house in Georgia, I Emailed him explaining my situation and I sent the chip to him so he could tell me what the chip was for. He told me that the chip had programming in it to change the fuel values, delete the RPM redline, and other little performance tweaks.
I gave him the “ blueprints” to what I wanted to modify, which included cam, injectors, heads, ported TPI , coolant temp values and the deletion of VATS. He reprogrammed everything to the specs and the specs were inline with the mechanical upgrades and everything else I did. It was a total success. I never had any issues ever again. I’m not saying this is your problem, but my issue was a bad aftermarket chip and slapped on aftermarket parts that weren’t inline with the chips programming. Causing all kinds of problems . Hope this helps
I decided while still working on it at 1am that I was gonna just slap a carb/intake off a spare 305 I have onto it, but I will check the chip first. I just find it strange it ran great for a couple days then went downhill.
Re: 305tbi surges when accelerating. Runs really rich
Originally Posted by Purplestaff
I decided while still working on it at 1am that I was gonna just slap a carb/intake off a spare 305 I have onto it, but I will check the chip first. I just find it strange it ran great for a couple days then went downhill.
Today mine was running perfectly fine, I ran a few errands and all of its pickup was there, smooth idle etc. I was laughing because this is so strange. I did read something last night before making my original post, I was reading about the TBI fuel pressure regulator located behind the injectors . I think I have an issue with the regulator or a fuel pump ready to go. Check this out
Re: 305tbi surges when accelerating. Runs really rich
Originally Posted by Syo1989Ta
Today mine was running perfectly fine, I ran a few errands and all of its pickup was there, smooth idle etc. I was laughing because this is so strange. I did read something last night before making my original post, I was reading about the TBI fuel pressure regulator located behind the injectors . I think I have an issue with the regulator or a fuel pump ready to go. Check this out
I have rebuilt the tbis before, might do this one. Or see if i have another one sitting around. I do have a tune chip in mine, hypertech. I think I have another tbi computer around somewhere.. I'll see.
Re: 305tbi surges when accelerating. Runs really rich
Originally Posted by Purplestaff
I have rebuilt the tbis before, might do this one. Or see if i have another one sitting around. I do have a tune chip in mine, hypertech. I think I have another tbi computer around somewhere.. I'll see.
No kidding? I’m guessing those chips go bad after time. When reading your original post, the very first thing that came to my my mind was the ECM chip. I’ll never forget that job as long as I live, I almost dumped the car because I couldn’t figure it out. That job inspired me to buy the factory service manual. All the advice I gotten was parts replacement, and to me, that’s not how to learn. I’m going to check for a chip on my Ecm too tomorrow. I seriously doubt it though
09-28-2024, 11:48 PM
