98 burban, 5.3., TBI. came in for an intake gasket. tried to leave...but owner and we (the shop) feel it has a lack of power (drive) after we touched it. we have re-done the intake 3 TIMES...3rd time we did it by the book. have replaced new sparks, spark wires, cap, rotor. We tried a new EGR solenoid valve...no change. New MAP sensor... to no avail. New O2 sensor. ALL connections (sensors, wiring harness) are connected. Timing is correct (0 degrees) and is advancing properly (10 degrees + with RPM). once, a sulphur smell came from tailpipe...went away. also in park, or under heavy load, SOME black smoke comes from Tailpipe. Drilled "speedholes" (shop joke) in tailpipe before cat. conv...gave a very slight increase in power. We thought that cat. conv. is choked. Now it's thought that the EGR valve is bad. Oil is clean, and it could use a slight amt of ATF.
I personally (as well as the shop) would very much appreciate a viable solution to get this POS out of our bay.
2006-07-01 05:30:22 · 4 answers · asked by Ryan 4 in Cars & Transportation ➔ Car Makes ➔ Chevrolet
Thank you all for your responses! After everything we changed and checked….we advanced the timing to 14 ATDC instead of 0 TDC like the book and Chevy say. Now, the Suburban (’94, not ’98, I was mistaken) has very good power to the rear end. We may still attempt to convince the customer to change the Catalytic Converter as a proactive maintenance measure as well as for fuel economy. One of the fellows in the shop still wants to change out the EGR valve solenoid…
2006-07-07 05:05:14 · update #1
With all the above being done,,have you actually tryed taking the egr valve off and inspecting it,,also you might want to check the slack in the timing chain,,i just re-paired one that the customer had spent over two grand on at one shop,,and we almost had to have it towed to my shop,,the first thing i did was pull the cover,,and it wasn't hard to see why it did,nt have any power,,and sometime,s the more you try to find something,,the harder it will be to find,,been doing this for a living for 35 yrs,,and have had a lot of the chevy,s and gmc,s in here for timing set,s,,sound,s like you all have covered everything else,,hope this help,s.
2006-07-06 17:21:22 · answer #1 · answered by dodge man 7 · 2⤊ 0⤋
depending where the gasket was leaking originally? if it was leaking into the intake system rather than just leaking oil there is a possibility that the "long term fuel trim" in the computer has "learned" to adjust for this problem. try removing BOTH battery cables and touching them together for a few seconds to reset the fuel trim and all memory in the computer. if this does not take care of the problem there is a chance that too much fuel has gotten into the cat. convertor and has plugged it (also accounting for the smell). cut the exhaust in front of the convertor and drive it to check.
2006-07-01 22:42:38 · answer #2 · answered by Anonymous · 0⤊ 0⤋
check maf output and verify if it is running rich under a load by watching o2 sensor output if it is throttle by wire be sure demanded throttle and actual output is correct if you suspect a maf you could try cleaning it with windex but be careful or you could be eating another part have you checked for fuel filter clogging? could also try dropping exhaust to rule out a collapsed pipe or restricted exhaust good luck
2006-07-01 21:39:41 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Black smoke?? Stick your finger in the exhaust and sample what is on the inside, is it "oily" and black?? Check the compression, it may need rings/pistons. Nye
2006-07-06 01:08:32 · answer #4 · answered by teasinglittlebrat 3 · 0⤊ 0⤋