I just bought a 1988 W100 with the 318 and am having some issues with either the throttle body and/or the fuel injectors. I replaced both fuel injectors last month because one of them was not working. The first time I drove it after getting everything back together the truck was hesitating and sputtering until I finally sunk the pedal to the floor it sputtered and hesitated and then it started running fine. Now, I am seeing a similar problem. It started out first when I would drive it in town at slower speeds and also on the trails (15mph or so), the truck would just not go and it would stall. After restarting, which took a little while, their would be brown smoke coming from the exhaust. Once you sat their and reved it up the smoke would eventually go away. Up until yesterday the truck would run fine at highway speeds (55-75) but now it is not. I have to keep the petal all the way down to the floor on the road just to keep the truck running. Once I start slow down the truck will start acting up. My thought is the truck is getting overloaded. It seems as if one of the sprayers is sparatically working now. But am not really sure. Any suggestions would be greatly appreciated.
threetwos
01-06-2009, 01:54 PM
They 'spray' or are energized alternately with a dual plane intake manifold. A noid light will instantly tell if they are working. They attach to the top of the electrical connectors and light when the circuit is completed or the injectors are grounded,(open), by the PCM. Your problem could be a number of things such as the coolant sensor or the TPS,(throttle position sensor). Are you getting any codes from the diagnostic scan tool if you have one? If not you can retrieve codes from the check engine service engine light on the dash by cycling the ignition key 3 times and leaving the ignition key on on the third cycle.
vaughnej2002
01-06-2009, 08:02 PM
I will either get a diagnostic tool this weekend and/or try your suggestion with the ignition key to see if I am getting any codes. Let you know what I find out. Thanks
360 WarLock
01-07-2009, 11:37 PM
did you disconnect the batt. to reset the ecu after you changed the injector's? I had the same thing with my now gone 90 with a 360 (5.9). also didnt say if they were new(very costly), or reman"s. I went with the reman's, and had to replace one set because of a bad injector, make sure they are the right size, the truck use's a differant one than the car's did.( found that out also)One other thing I came across, make sure you get the one's closest to your build date, In 90 there were some mid. run changes, and differant supplyer's. I think we went with the nitto's, think that or the bosch.
vaughnej2002
01-08-2009, 05:24 PM
No, I did not disconnect the batt to reset the ECU. I will try that. I bought NAPA's brand of injectors, brand new not rebuilt. When I called NAPA to get the injectors I did tell them the year and make. The ones that I took out of the truck where bosch. I am currently working nights so have not had a chance to go anything to the truck, but once I can I will let you know. Thanks.
vaughnej2002
01-24-2009, 10:23 PM
I disconnected the battery in an attempt to reset the ECU and also tried cycling the ignition key to get any codes. Neither worked. Any other suggestions would be greatly appreciated. Thanks
vaughnej2002
02-25-2009, 06:09 PM
Thought I would give an update on this issue. There were 3 different problems that I found and fixed and now the truck is running great. First off some of the vacume hoses going into the Throttle Body were incorrectly hooked up. I fixed that first and still had the issue of the truck overloading. Next I discovered that the Throttle Body Temperature Sensor was bad. I replaced that and still had the same issue of the truck overloading. At this point, due to not having enough time to devote to fixing the issue, I brought it to my mechanic and he found that the Coolant Temperature Sensor was not working correctly and that it was showing the engine being cold when it was hot and therefore would be dumping to much fuel in. He replaced that and now the truck is not overloading anymore.
jbracefan1977
03-13-2009, 02:31 AM
Thought I would give an update on this issue. There were 3 different problems that I found and fixed and now the truck is running great. First off some of the vacume hoses going into the Throttle Body were incorrectly hooked up. I fixed that first and still had the issue of the truck overloading. Next I discovered that the Throttle Body Temperature Sensor was bad. I replaced that and still had the same issue of the truck overloading. At this point, due to not having enough time to devote to fixing the issue, I brought it to my mechanic and he found that the Coolant Temperature Sensor was not working correctly and that it was showing the engine being cold when it was hot and therefore would be dumping to much fuel in. He replaced that and now the truck is not overloading anymore.
thanks for posting this in detail. my brother's truck has been giving him troubles lately, will try to tell him about this. hope it will fix his own problems. thanks
