| Author | Message | ||
     Jim H. (Victor_mature) Member Username: Victor_mature Post Number: 81 Registered: 02-2003 |
94 D1 w/106K has been idling high on hot start, around 2K for 10-15 seconds, before settling back down to normal. About a week ago, it also began idling a little rough and even stalled once. I pulled the stepper motor and cleaned it (pretty dirty) and sprayed brake cleaner to clean up the seat. Started right up but idled pretty clumsily, then cleared up but the check engine light came on. I took off the inlet hose (and MAF) and cleaned up the butterfly valve inside the plenum chamber, as it was pretty sludgy – I didn’t do anything to the MAF. When I went to start it, idled a little rough, then smoothed out nicely. I disconnected the battery for 5 seconds and then started it again. Hot start high idle was still there but check engine light went out and idle was smooth. Oh, and check engine light offered no code on the OBDI under the passenger seat. Still looking for the hot start problem, I checked the vacuum line to the pressure regulator (thank you DiscoWeb) and found it to be rotted and cracked. Replaced it and hot start high idle was much better but still there (about 1500 for maybe 5 seconds). Status: Check engine light out, idle very smooth, hot start high idle greatly improved. Cut to today: A recent change of heater bypass/valve-inlet hoses led to cracked heater bypass valve. I replaced it (in a parking lot under a tree) but spilt a considerable amount of coolant down onto the exhaust manifold and onto the lamda sensor, which I only mention because now I’m getting the full version of the hot start high idle (about 2K for 15 seconds) and the Check Engine light has returned along with a rough and jumpy idle. –although still no code on the OBDI. (remember this is a 94 so this is the older, shittier version of the OBDII). If I disconnect the battery for a few seconds and restart, the check engine light will stay off and idle is smooth but has twice returned (both the light and the lumpy idle). High idle at hot start seems to be back for good. Questions: Could either the brake cleaner sprayed into the plenum chamber or the coolant across the lamda sensor have anything to do with this? At no point did engine overheat and after high idle dies down the truck is very smooth and drivable, but when idle begins to hiccup the check engine light comes on and stays on, even if idle eventually smooths out. Answers? I’m supposed to be heading out on a road trip in a few days and the thing has me a little worried. Jim | ||
| Tony Zuniga (Tony23007) Member Username: Tony23007 Post Number: 67 Registered: 05-2003 |
Jim, I was suffering from high idle as well, but one of my other problems was the car was hard to start when cold. I finally figured out that I had three bad fuel injectors, the dealer told me that the injectors were leaking a lot of gas into the chamber and that is why I was getting high idle at starts, the excess gas was burning up inside the chamber once the gas had burned out the idle came back to normal!! I don't know if this is your problem but it's worth checking up on it. | ||
| Jim H. (Victor_mature) Member Username: Victor_mature Post Number: 85 Registered: 02-2003 |
Thanks Tony, does anyone have any info on testing injectors, identifying faulty ones or confirming that they might be the problem? Or any other input? I understand that my question isn't as interesting as "Which oil should I run?" but I'm hoping for some help. Thanks, JH |
