bonehead Posted October 30, 2011 Share Posted October 30, 2011 i swear there was a topic on this but i can't find it so i guess i'll ask it again. my 91 pathy bogs and missfires @ 2800-3000rpm and will not go pass that. i changed my dizzy, rotor, plugs, wires, feul filter and feul pump also cleaned the MAF. what else can i look into that might be the problem Link to comment Share on other sites More sharing options...
ejin4499 Posted October 30, 2011 Share Posted October 30, 2011 check the manual look for limp home mode Link to comment Share on other sites More sharing options...
sewebster Posted October 30, 2011 Share Posted October 30, 2011 Trouble codes? Link to comment Share on other sites More sharing options...
devonianwalk Posted October 30, 2011 Share Posted October 30, 2011 Have you checked the timing? If its off just a degree or two it would sound fine at lower rpm's but show its ugly head at higher revs. Link to comment Share on other sites More sharing options...
bonehead Posted October 30, 2011 Author Share Posted October 30, 2011 ok i got a code 34- knock sensor. will the knock sensor make the engine act this way?? if so is it an easy fix?? Link to comment Share on other sites More sharing options...
sewebster Posted October 30, 2011 Share Posted October 30, 2011 If your engine computer thinks your engine is knocking because of the knock sensor, then yes, the engine will perform poorly. The knock sensor is held on by a single bolt, and has a single electrical connector, BUT it is under the lower intake manifold, so either you have to do a lot of disassembly to get to it, do a lot of wiggling from the rear, or bypass/relocate it by disconnecting upstream. I suppose it's also possible that the sensor is working properly and is retarding engine performance to prevent knock... but probably you just have a bad sensor. Link to comment Share on other sites More sharing options...
Tungsten Posted November 3, 2011 Share Posted November 3, 2011 This might sound stupid but what kind of gas do you use? 1 Link to comment Share on other sites More sharing options...
bonehead Posted November 4, 2011 Author Share Posted November 4, 2011 regular gas from chevron. but i'm kinda leaning towards the knock sensor. Link to comment Share on other sites More sharing options...
bonehead Posted November 4, 2011 Author Share Posted November 4, 2011 to relocate the knock sensor where will i find the old knock sensor wire? what color? i have a 91 vg30e. Link to comment Share on other sites More sharing options...
sewebster Posted November 4, 2011 Share Posted November 4, 2011 Try to feel behind the engine. The knock sensor wire is the only thing that is coming out from below the lower intake, in the valley between the two cylinder heads. Link to comment Share on other sites More sharing options...
Tungsten Posted November 4, 2011 Share Posted November 4, 2011 regular gas from chevron. but i'm kinda leaning towards the knock sensor. what octane? Link to comment Share on other sites More sharing options...
adamzan Posted November 5, 2011 Share Posted November 5, 2011 (edited) What octane of gas you use won't affect it. It is designed to run on 87. Edited November 5, 2011 by adamzan Link to comment Share on other sites More sharing options...
Towncivilian Posted November 5, 2011 Share Posted November 5, 2011 What octane of gas you use won't affect it. It is designed to run on 87. Well, running higher octane can make it run worse or get worse gas mileage since higher octane is more difficult to ignite. Link to comment Share on other sites More sharing options...
sewebster Posted November 5, 2011 Share Posted November 5, 2011 If it's knocking then using higher octane gas might actually help. Link to comment Share on other sites More sharing options...
bonehead Posted November 6, 2011 Author Share Posted November 6, 2011 (edited) well i relocated the knock sensor and the code went 55 but the truck still runs like crap. could it be the oil?? i had it changed at a lube shop befor all this happend and it started runnin like crap the next day. i think they put 5w30 is that to thin? i usely use 10w30 on all other cars. Edited November 6, 2011 by bonehead Link to comment Share on other sites More sharing options...
sewebster Posted November 6, 2011 Share Posted November 6, 2011 so you still can't go past 3k rpm? Link to comment Share on other sites More sharing options...
bonehead Posted November 6, 2011 Author Share Posted November 6, 2011 nope cant go over 3000rpm. ecm give code 55 so now i'm lost dont know what to look for now. Link to comment Share on other sites More sharing options...
Towncivilian Posted November 6, 2011 Share Posted November 6, 2011 5W-30 is fine. You want as thin as possible, but as thick as necessary when it comes to engine oil (and of course within the manufacturer's recommendations - don't run a 0W-20 in a VQ35, for example). Just a random idea, maybe disconnect the negative battery terminal to reset the ECU and see what happens? Link to comment Share on other sites More sharing options...
bonehead Posted November 6, 2011 Author Share Posted November 6, 2011 ok reset ecu still same results. umm how many heat sesors are there? askin cause it acts up when warm and running for more then 15-30 min. Link to comment Share on other sites More sharing options...
sewebster Posted November 7, 2011 Share Posted November 7, 2011 Hmm. Interesting that you have no code but it seems to be in failsafe mode. I would try wiggling/adjusting the MAF wiring to see if that does anything I guess. Maybe something happened when you cleaned it somehow... Link to comment Share on other sites More sharing options...
ejin4499 Posted November 7, 2011 Share Posted November 7, 2011 check your voltages at your maf if you damaged the heater in it you would be put in limp home mode. Link to comment Share on other sites More sharing options...
Tungsten Posted November 7, 2011 Share Posted November 7, 2011 What octane of gas you use won't affect it. It is designed to run on 87. The reason I was asking is because some states offer as low as 85 octane fuel (considered safe for higher altitudes), which isn't very good for this particular engine. Here is something to try: Unplug the battery for a minute and plug it back in. See if it runs good for the first few minutes while it gets up to temp. Link to comment Share on other sites More sharing options...
bonehead Posted November 7, 2011 Author Share Posted November 7, 2011 hmmm heater in the MAF? ok so how do i check the MAF? what should the normal readings be? Link to comment Share on other sites More sharing options...
bonehead Posted November 7, 2011 Author Share Posted November 7, 2011 truck runs when cool but once it warms up in temp. it starts to bog out like faulty plugs but i changed my plugs and wires. maybe the MAF is broken but how do i check it? Link to comment Share on other sites More sharing options...
sewebster Posted November 7, 2011 Share Posted November 7, 2011 You can tap into the wires at the MAF or at the ECU with a multimeter. The correct voltages are in the EF/EC section of the FSM. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now