Brief history: Had timing chain, chain guides and tensioner replaced 4 years ago. Within the same week, I installed the JWT ECU. Went from 27-28 mpg mixed (street and hwy) to about 20-21 mixed.
FF to July 2001: Had clutch replaced...f*cked up mechanic screwed with SOMETHING (STILL haven't figured out what yet) so that both warm and cold idle are screwed up (runs SO rich that it stalls when first starting it and idles low at cold idle (750 RPM) and warm idle (about 600 RPM). At warm idle and 600 RPM w/JWT motor mounts, the thing shakes like a MF!
(BTW: the EGR and other disc-shaped thing next to EGR have been disconnect for about 5 years, so that is NOT part of the problem. I also checked the ECU for codes (5 and 5 - no sensor problems, and have reset the ECU).
Tuesday this week: Took NX to Rosen Autosport in Richmond. Explained the problem and everything I've done to it in the last 3 months to try to fix the idle problem (replaced vacuum lines, PCV valve, O2 sensor, coolant temp sensor, new plugs, wires, distributor cap and rotor), to no avail. After setting the timing (15 degrees), they noticed that the distributor was most of the way to the firewall side of the adjusting slot. Then, we checked the 3 month old plugs (stock NGK platinums); they were already fouled!
Joe at Rosen's theory: The timing chain is off one tooth on the exhaust cam. Basically, the intake and exhaust cams are out of sync with each other! When I ordered a new VC and spark plug gasket and new plugs from Courtesy, I actually got to talk to Brian (from the forum). When I explained to him the problem and possible cause, he told me that 1 tooth off would be something like 20 degrees difference in timing!!!
I'm having them check it next week after the parts come in. I will also have them set the timing, adjust the idle mix, and anything else we can set relating to air/fuel mixture). I STILL think something else is hosed relating to the idle, but after this is fixed, at least I'll be working with a properly timed engine, intake AND exhaust! I'm actually hoping the exhaust cam is one tooth off, now; when fixed, I should get better mileage, a smoother engine, and, hopefully, a bit more power!
If anyone could shed some light on this idle problem, please post it here.
TIA,
al
FF to July 2001: Had clutch replaced...f*cked up mechanic screwed with SOMETHING (STILL haven't figured out what yet) so that both warm and cold idle are screwed up (runs SO rich that it stalls when first starting it and idles low at cold idle (750 RPM) and warm idle (about 600 RPM). At warm idle and 600 RPM w/JWT motor mounts, the thing shakes like a MF!
(BTW: the EGR and other disc-shaped thing next to EGR have been disconnect for about 5 years, so that is NOT part of the problem. I also checked the ECU for codes (5 and 5 - no sensor problems, and have reset the ECU).
Tuesday this week: Took NX to Rosen Autosport in Richmond. Explained the problem and everything I've done to it in the last 3 months to try to fix the idle problem (replaced vacuum lines, PCV valve, O2 sensor, coolant temp sensor, new plugs, wires, distributor cap and rotor), to no avail. After setting the timing (15 degrees), they noticed that the distributor was most of the way to the firewall side of the adjusting slot. Then, we checked the 3 month old plugs (stock NGK platinums); they were already fouled!
Joe at Rosen's theory: The timing chain is off one tooth on the exhaust cam. Basically, the intake and exhaust cams are out of sync with each other! When I ordered a new VC and spark plug gasket and new plugs from Courtesy, I actually got to talk to Brian (from the forum). When I explained to him the problem and possible cause, he told me that 1 tooth off would be something like 20 degrees difference in timing!!!
I'm having them check it next week after the parts come in. I will also have them set the timing, adjust the idle mix, and anything else we can set relating to air/fuel mixture). I STILL think something else is hosed relating to the idle, but after this is fixed, at least I'll be working with a properly timed engine, intake AND exhaust! I'm actually hoping the exhaust cam is one tooth off, now; when fixed, I should get better mileage, a smoother engine, and, hopefully, a bit more power!
If anyone could shed some light on this idle problem, please post it here.
TIA,
al