Boiler74 Posted September 30, 2006 Share Posted September 30, 2006 Ok, so I had the Comanche up on jackstands today. Was able to start it a couple of times up on the stands, no problems. After I put it back on the ground, it wouldn't start. I was working on the body and the interior, so I didn't do any engine work, besides changing the air filter. But now it turns over, sounds like it wants to catch, and even will briefly, but then dies. I thought maybe I had accidently messed up a vacuum line to the fuel injection system when I changed the filter, but I can't find anything wrong. It's an 89 with the I6, 5 spd, 4wd. Any advice would be appreciated. J. Link to comment Share on other sites More sharing options...
Wildman Posted October 1, 2006 Share Posted October 1, 2006 Boiler - I would guess that you might have bumped the fuel pump resistor, White porcelain conector, about 3" long, with 2 orange wires on each end, this is right above the air cleaner, and controlls curent to the fuel pump. and if you are cranking and will not start, the fuel is not getting to the rail. Check this out first, Advance auto parts have this in stock if yours is shot. Good luck ;) Pete M supplyed the picture, we had this coulpe of weeks ago Hope you don't mind me posting your picture of this Pete :bowdown: Link to comment Share on other sites More sharing options...
Eagle Posted October 1, 2006 Share Posted October 1, 2006 The fuel pump ballast resistor isn't necessary, it's only to make the fuel pump run quieter. The 87s don't have it. Which means for diagnostic purposes you can just jumper the two wires together. If it starts and stays running, you've identified the problem. Since you changed the air filter, there's a good chance you may have whacked that thing without realizing it. Link to comment Share on other sites More sharing options...
Boiler74 Posted October 1, 2006 Author Share Posted October 1, 2006 Thanks, I'll give that a try this morning. J. Link to comment Share on other sites More sharing options...
Boiler74 Posted October 1, 2006 Author Share Posted October 1, 2006 Ok, so I jumpered the fuel pump resistor and still no luck. Pulled the plugs and checked them over, and they're fine. The truck will catch once in a while, and run for a second or so, but when it does, it runs so rough as to shake the entire truck. So I'm at a loss. Any other ideas? J. Link to comment Share on other sites More sharing options...
Pete M Posted October 1, 2006 Share Posted October 1, 2006 When you say "body work", does that include welding? It's a rare occurance, but people have fried electrical parts if the welding juice tries to find an alternate path or 2 around the truck. Link to comment Share on other sites More sharing options...
Wildman Posted October 1, 2006 Share Posted October 1, 2006 Good point Pete Link to comment Share on other sites More sharing options...
Boiler74 Posted October 1, 2006 Author Share Posted October 1, 2006 No, no welding work. Just sanding and removing decals to get ready to paint. I did mess with the transfer case for a short time, but that doesn't have anything to do with the engine running. I double checked the vacuum lines to it just to make sure they were hooked up..... not even sure if that would have anything to do with the engine starting. Like I said, I'm at a loss. Is there any way to check the that the fuel pump is working correctly besides getting a pressure guage? I just don't understand this, because I was able to just reach in and start it two or three times when it was on the stands, and now it won't run. I know it's probably something simple, but I can't find it. Thanks for the help so far. Josh Link to comment Share on other sites More sharing options...
mike Posted October 1, 2006 Share Posted October 1, 2006 here's a quick way of seeing if the pump even works, turn the ignition to on and listen for a humming sound coming from the gas tank. should humm for a few seconds a least and then stop. don't turn on the engine when doing this just turn key to on. your guages and lights should come on but not the starter to crank it over. if there is no humming then i bet the pump isn't working for some reason, maybe a wire got jarred lose when you took it off the stands? if there is a humming then i would say the pump works but the fuel might not be getting to the engine. i know the fuel line is metal except for the connector hoses for the filter but i'm sure you have noticed if you accidently crushed it with the jack. also check for any blown fuses. kinda strange why it would start on stands but not after it's back on the ground. Link to comment Share on other sites More sharing options...
feerocknok Posted October 1, 2006 Share Posted October 1, 2006 You could probably put fuel into the throttle body with a pepsi bottle and see if it keeps going. Did that to check if one of my Yota motors was still good. Link to comment Share on other sites More sharing options...
Boiler74 Posted October 2, 2006 Author Share Posted October 2, 2006 Went out tonight real quick and can hear the fuel pump humm when the ignition is turned to on. So I guess that's ok. Starting to run out of ideas. Any more would be helpful! Josh Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 2, 2006 Share Posted October 2, 2006 is there gas in it? having it on jackstands might cause a tiny bit of gas to go to the right spot and it ran but now that its on flat land its not enough? (somebody had to ask :roll: ) Link to comment Share on other sites More sharing options...
Boiler74 Posted October 2, 2006 Author Share Posted October 2, 2006 Yep, it does have gas in it. Figured someone would ask! J. Link to comment Share on other sites More sharing options...
feerocknok Posted October 2, 2006 Share Posted October 2, 2006 Take the fuel line off right before it connects to the throttle body, put it into a gatorade bottle or whatever, turn the key to the 'on' position. The fuel pump should be able to send fuel into the bottle. If not, it's inbetween the pump and the throttle body. Link to comment Share on other sites More sharing options...
Boiler74 Posted October 6, 2006 Author Share Posted October 6, 2006 I finally got some time to spend on the Comanche. I disconnected the fuel line from the fuel rail and put it in to a bottle and cranked it over, and I am getting fuel. Now what? I've jumped the fuel pump resistor, so that's not in the loop any more. But, unlike before, when the engine would catch a little, now it doesn't at all. So I don't know what to do now, except yell for help. I know I need to now check if I'm getting spark, but I can't do that until I get someone to help out here (I live in the sticks). Any other advice? J. Link to comment Share on other sites More sharing options...
87manche Posted October 6, 2006 Share Posted October 6, 2006 try fogging some ether in the intake. If it cathes you've got a fuel problem, if not it's spark. To test for spark rig up a remote starter wire. Pull the green wire that goes to the start, and jumper it to the positive terminal of the battery. Make sure it's not in gear, the motor will turn over. Link to comment Share on other sites More sharing options...
JOMJ87 Posted October 6, 2006 Share Posted October 6, 2006 the make a spark plug tester you can use to make it easier or make a push button start and hook it up to the starter so you don't need a partner for help. You can look up how to make the push button starter that just uses clamps Like a jumper cable just smaller connected to the starter. Just trying to help you solve this ASAP. Cole Link to comment Share on other sites More sharing options...
possum Posted October 6, 2006 Share Posted October 6, 2006 Have you changed the fuel filter? Or has it been ran real low on gas or run out of gas completely? If so your injectors could be clogged. Link to comment Share on other sites More sharing options...
Boiler74 Posted October 7, 2006 Author Share Posted October 7, 2006 Ok, so I blasted it with starting fluid and it fired for a few seconds. Guess I have spark. So, do I now start with the fuel filter? Then work my way down the line of the fuel system? It hasn't been ran out of, or run low on gas, but the gas is a little old. I couldn't see that being the whole problem, but maybe contributing to it? Guess I'll start with the fuel filter, and maybe drain the gas out and get some new stuff. How hard is it to drain that tank? J. Thanks for all the help, by the way. Link to comment Share on other sites More sharing options...
steve Posted October 7, 2006 Share Posted October 7, 2006 I had an issue like that with my truck a while back. and it turned out to be a ground wire off on the engine block. Its located on passenger side just above and to the back of the oil sending unit. I can't say thats your problem. just an idea. Link to comment Share on other sites More sharing options...
CWLONGSHOT Posted October 7, 2006 Share Posted October 7, 2006 Ok, so I blasted it with starting fluid and it fired for a few seconds. Guess I have spark. So, do I now start with the fuel filter? Then work my way down the line of the fuel system? It hasn't been ran out of, or run low on gas, but the gas is a little old. I couldn't see that being the whole problem, but maybe contributing to it? Guess I'll start with the fuel filter, and maybe drain the gas out and get some new stuff. How hard is it to drain that tank? J. Thanks for all the help, by the way. How much gas is in the tank? If less than a 1/4 tank I wouldn't worry about draining. You are right to start with the filter, its a easy job and should likely be done anyhow. After that I would check the fuel pump. When you first turn the key, before the starter catches, you should hear the pump prime the line. If you don't, its likely the pump is shot. Try that and get back to us. Good luck, CW Link to comment Share on other sites More sharing options...
Boiler74 Posted October 7, 2006 Author Share Posted October 7, 2006 The tanks about 3/4 full, so I think I'll drain it. I can hear the pump humm, so I think that's ok. I get fuel out of the fuel line running into the fuel rail for the EFI when I crank it over, but I don't know if it's enough. Guess all I can do is start at one end and work my way to the other. The ground strap looks ok. Thanks, Josh Link to comment Share on other sites More sharing options...
JOMJ87 Posted October 7, 2006 Share Posted October 7, 2006 have you pulled the injectors to see if they r good. I knwo you tried most of the others but if fuel is getting to the rail and it fires with starter fluid then maybe fuel isnt reacing the injectors or coming out incorectly. Cole Link to comment Share on other sites More sharing options...
Wildman Posted October 7, 2006 Share Posted October 7, 2006 Boiler - How long did you have the Mj on the jack stands?? and when was the last time you started it, that it ran?? If you had it sitting for couple for months, even 2 months, the gas might have gone bad, if you take off the gas cap, and it smells like Varnish, thats bad gas. You can save some trouble by adding Fuel Stabilizer to the gas in the tank, but still change out the filter. Let the Stabilizer sit over night, and see if it will start and run. Link to comment Share on other sites More sharing options...
Pete M Posted October 7, 2006 Share Posted October 7, 2006 Even with bad gas it should at least try to start. The gas in my 88 was almost 2 years old when I finally fired it up, but the truck still ran. It ran poorly, but it ran and idled. I dumped in some stabilizer and some octane boost and it ran and drove just fine. Link to comment Share on other sites More sharing options...
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