armelius2 Posted February 8, 2005 Share Posted February 8, 2005 (edited) Can anyone help me figure this out. Backfires usually around 1200 rpms and hard acceleration after the rpms are going down. Is there just one pcv valve? I am probably going to replace fuel filter and nearly everything else to include the spark plugs except the fuel injectors which are over 300 apiece. Edited February 8, 2005 by armelius2 Link to comment Share on other sites More sharing options...
denisb Posted February 8, 2005 Share Posted February 8, 2005 (edited) Aren't carb/throttle body backfires usually due to bad timing? maybe check the timing. Edited February 8, 2005 by denisb Link to comment Share on other sites More sharing options...
94extreme Posted February 8, 2005 Share Posted February 8, 2005 you got a carb on your truck??? wtf? timing issue is normally associated with backfires... Link to comment Share on other sites More sharing options...
armelius2 Posted February 8, 2005 Author Share Posted February 8, 2005 fuel injection. I pulled the codes from the computer and it gave me a fuel injector leak, air flow meter circuit as well as the Cylinder head/water temperature sensor circuit. The injector may be showing a leak because I removed one screw to the injector cover and didn't put any locking sealer on it. Could be an O ring went bad. Has anyone replaced their fuel injectors? Link to comment Share on other sites More sharing options...
94extreme Posted February 8, 2005 Share Posted February 8, 2005 sounds like a few things to deal with.. get new sensors and tighten up the FI and you should be good... Link to comment Share on other sites More sharing options...
armelius2 Posted February 8, 2005 Author Share Posted February 8, 2005 O2 sensor? Right now I have to replace the pcv hose. That thing was very brittle at the ends and hard as chinese plastic. Link to comment Share on other sites More sharing options...
88pathoffroad Posted February 9, 2005 Share Posted February 9, 2005 The injectors aren't all that hard to replace if you have tools and a place to do it, but it's definitely not a side-of-the-street job. I had to make a special punch tool to knock the injectors loose on mine. Other than that, it's disassembly and reassembly. Link to comment Share on other sites More sharing options...
armelius2 Posted February 9, 2005 Author Share Posted February 9, 2005 A punch tool? I bought ngks spark plugs for the heck of it. Have to wait on this hose now. Anyone replace their AB valve? I really hate waiting for parts. I remember when if you had a foreign auto you had to take it to a specialist perhaps because of the metric system but you also had to wait weeks before they shipped the stuff on the slow boat. Link to comment Share on other sites More sharing options...
thndrwhls Posted February 9, 2005 Share Posted February 9, 2005 I had a similar problem wiht mine, it would backfire through the tbi and hesitate often but more so when damp or cold. Nissan told me I needed a $1600.00 throttle body replacement, turns out after some thinking and investigating it was merely the thermostat. I had noticed that the motor wouldnt heat up if it were real cold outside, well guess what, the engine temperature sensor controls the fuel mix. A new thermostat and its amazing the difference, she is still a dog with not much power but at least I can tell that she is giving it all she's got now... Thorleys on the way this summer and cams hopefully by next spring, already got the RS9000's and a magnaflow catback setup. Good luck man... Joe Link to comment Share on other sites More sharing options...
88pathoffroad Posted February 9, 2005 Share Posted February 9, 2005 There's only one PCV valve, and the AB valve just has two hoses going to it, then a single mounting bolt. Very easy to replace. The cylinder head temp sensor, now that's another whole pot of nails....it's right by the thermostat housing, on the block or head, can't quite remember which. Link to comment Share on other sites More sharing options...
94extreme Posted February 9, 2005 Share Posted February 9, 2005 O2 sensor? Right now I have to replace the pcv hose. That thing was very brittle at the ends and hard as chinese plastic. not the O2 but the ones that the ECU through out codes for.. 88 just grimaced about one of them just above... new thormostat may be in order also... Link to comment Share on other sites More sharing options...
armelius2 Posted February 9, 2005 Author Share Posted February 9, 2005 Going to replace the thermostat. The pcv hose cost 20 bux and is three or more days away. BS. Link to comment Share on other sites More sharing options...
armelius2 Posted February 9, 2005 Author Share Posted February 9, 2005 That thermostat sure is difficult to get to. Link to comment Share on other sites More sharing options...
88pathoffroad Posted February 10, 2005 Share Posted February 10, 2005 You could have used generic vaccuum hose for the PCV valve and cut it to fit... Link to comment Share on other sites More sharing options...
armelius2 Posted February 10, 2005 Author Share Posted February 10, 2005 One side is larger than the other. There is no generic or adapters. Link to comment Share on other sites More sharing options...
CT Pathy Posted February 21, 2005 Share Posted February 21, 2005 My 89 Pathy (V6 5 speed, 4x4) has been backfiring through the intake for a few years now...Only on deceleration, accelleration is totally fine. I have a set of Pacesetter headers K&N filter and a Borla catback on it. Had someone check the timing, Changed the thermostat, AB valve,PCV Valve, vacuum lines, air filter, the little breather filter inside the air cleaner....still doing it. It is actually blowing oil out of the K&N filter all over the inside of the air cleaner housing. It happens right at 1500 RPM consistently. I am totally out of ideas. I have been chasing the problem for about 3 years now, just throwing money at it and I still have no answers... Link to comment Share on other sites More sharing options...
88pathoffroad Posted February 21, 2005 Share Posted February 21, 2005 armelius2: use the larger size and hose-clamp it on the small end. REAL easy. It's not a high-pressure line. CTpathy: $1 says your EGR valve passages are totally plugged up and your decel valve needs replacing. Have you run your ECU codes? Link to comment Share on other sites More sharing options...
armelius2 Posted February 21, 2005 Author Share Posted February 21, 2005 Too late already bought the hoses. My problem is same as CTPathy. Right about 15000 as the rpms decelerate and you punch it, the backfire occurs. What or where is the decel valve? I was thinking it might be the AB valve if anything. Haven't checked the codes after the plugs and thermostat install. Seems it's harder to get it to backfire though. Link to comment Share on other sites More sharing options...
CT Pathy Posted February 21, 2005 Share Posted February 21, 2005 Ok I havent checked the codes in a while or checked the egr valve operation ( you know, push on the bottom of the valve till the engine stumbles) in about a year and a half. So how do I go about cleaning out the egr passages in the motor? also is the declleration valve the same thing as the ab valve? Link to comment Share on other sites More sharing options...
armelius2 Posted February 21, 2005 Author Share Posted February 21, 2005 I haven't checked but last time I did I was getting injector leak, 23 and 12 or 13 or something like that. Link to comment Share on other sites More sharing options...
88pathoffroad Posted February 22, 2005 Share Posted February 22, 2005 CTPathy: you have to take the TBI off and get into the intake itself...removing the EGR valve itself would give you the opportunity to hose some carb cleaner in there, it may blow out the blockage after it eats into the carbon deposits long enough. Got a Chilton's manual? Link to comment Share on other sites More sharing options...
CT Pathy Posted February 23, 2005 Share Posted February 23, 2005 Going to get a manual in the next few days. The only code I have ever gotten was an injector leak. I got it once when I changed the injuctor about 4 years ago and the again about 3 months ago the CEL came on though I never got a chance to check the codes. But both times it went away without my doing anything. If I remember correctly I had tried to take off the EGR valve once before and was unable to do so because the threaded posts that it has to slide off of are too long to get it off. It hits the firewall before it can come off the posts.I am assuming then that I need to remove the whole intake to do this or can I get away with just loosening it enough to slide it away from the back of the intake manifold? Sorry for the long post... Link to comment Share on other sites More sharing options...
armelius2 Posted February 23, 2005 Author Share Posted February 23, 2005 I think my backfire is fixed. Link to comment Share on other sites More sharing options...
CT Pathy Posted February 27, 2005 Share Posted February 27, 2005 What did you do to fix it? Link to comment Share on other sites More sharing options...
armelius2 Posted February 27, 2005 Author Share Posted February 27, 2005 Thermostat change, new spark plugs NGKs and wire set, replaced pcv valve and the hoses which were on their last leg. It doesn't do it anymore. Link to comment Share on other sites More sharing options...
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