Well as a lot of you probably remember, there was a thread about a strange hesitation that a lot of us were experiencing posted back at the old board. I haven't had the funds yet to really try and figure out what it is, but its still bugging me.
Things I've noted.
*Doesn't always do it. (Did it all day yesterday, but not once today)
*More prevalent when A/C is on and/or is not warmed up yet.
*Goes away if you floor it.
*Only when in gear, so if you put it in nuetral or park at a light it will stop.
*Occasionally stops on its own and you can feel the idle smooth out and drop.
A few guesses...
*TPS
*Fuel Pump?
*Vacuum Leak
*Coil or distributor problem?
*Transmission
Now I'm just pretty much curious if anybody has any experience similar to what I've been going thru. Like I said, haven't had the time, or the money to really tear into it. I think Eric mentioned he was gonna have his checked out. Any luck on that?
Thanks!
Matt
Yes and no. Fuel system (pump, injectors, FPR, pressure) tested fine. However, my EVP tested bad so I got a new one installed...problem still exists. This weekend I'm changing the idle bypass valve, TAB and TAD sensors. It feels like an emissions problem....maybe something not opening or closing properly. If that's the case then what I'm doing should show an improvement, if not solve the problem. I'll report any progress when I get it.
I hope its not an emissions problem. I have to get my car inspected this month. I think the only emissions thing I haven't changed out, is the EGR valve.
Matt,
Good luck with the inspection. I FINALLY got mine to pass today. If you have too much trouble let me know and I can probably hook you up with a "friendly" inspector.
Thanks man. By the way, it was nice meeting you the other day.
i spent several years chasing that problem. Its now history but it is a DIY job if you feel comfortable pulling the injectors and replace the tiny screens in the top of each one. I just left mine out and added an extra fuel filter in line with my throttle body.
(http://memimage.cardomain.net/member_img_a/447667_91_full.jpg)
So the problem are the injectors
Will check them on my vacations :macgun:
Only if the screens are partally blocked.
I changed the idle bypass valve, TAB and TAD sensors yesterday. Also found a vacuum line off. Idle seems to be more level now, not hunting up and down. Everything seems to be a lot better now, although I think the problem is still there to some degree. I won't know for sure until I drive the car normally (to work and back) this week. Still no codes from the EEC. I may try replacing the EGR and see if that makes a difference, but for now things are better than they were.
Check out the PRO-M racing troubleshooting site. Lots of helpful tuning info. I did everything they say and my car runs sweet and picked up 1 1/2- 2 1/2 mpg.i hope this link works... i'm still pretty new at this :dunno: http://www.pro-flow.com
Thanks for all the info guys. Its time for me to get to work and see if I can find the problem now! :)
Normal driving showed the problem to be greatly diminished...but it still exists. On a cold start there is a slight hesitation. First 1-2-3 shift of the day shudders, then all subsequent shifts are fine (and it's a new trans with full fluid, so it's not the trans). About 2 miles down the road you can feel the car do a little shimmy and sputter. Once the thermostat opens the problem is again reduced but present nonetheless. It feels like a dead spot in the gas pedal....give it a little more and the car does nothing. Go a little more and the car kicks into passing gear, while popping and shuddering and sputtering through the exhaust. WOT seems to cure the problem completely. The TPS is new. So now that the new emissions parts showed an improvement I'm really leaning towards the EGR. Will replace that this week and report back.
Thanks for all the in depth info, it helps me out a lot!
I've noticed that mine is starting to clear up, as if it was something just stuck in the fuel system. I picked up some injector cleaner and I'm gonna run that thru there and see what happens. I haven't ran any in there in over a year....I need to check out that EGR as well. Never changed it and I'm trying to replace all of the old emissions stuff so i know what i got.
The problem ended up being the EGR valve. I threw an old one on (the original from my '86 convertible) and the car is driving almost like brand new. No popping, no sputtering, no hesitation at all. I can actually give the car throttle through corners now! There is still a high idle issue which I think is being caused by the MAP sensor. I'm changing that over today in the hope that it returns the car down to normal. Other than that, just some cleaning of the throttle body and I should be good to go.
You can try to clean out the EGR with carb/choke cleaner and see if that helps things. I've done it before....it only buys you a little extra time before you absolutely must break down and shell out for a new one. But it can give you an indication of what's wrong anyhow. Worth the half hour or so that you'll be messing with it.
Well yesterday morning I took off the EGR and inspected it and there was a tad bit of build up on the part that plugs and opens the vacuum, but other than that, it still seemed to be clean and working ok. The plunger part still opened and closed properly from what I could tell. Well I popped it back on cause I had to go get it inspected, and passed with REALLY good numbers actually. Also the hesitation seemed to have been cleared up a lot, so it probably does just need to be changed...but during the course of this, somehow my AC went out. Theres no voltage getting to the clutch. Theres power at the pressure control switch, but none getting to the diode that goes to the clutch... :( I didn't blow a fuse either, so I don't think its caused by a short. :dunno:
Well........
I got fed up and said "I'll leave it to the pros" and made the mistake of dropping it off at a local dealership yesterday morning. I told them about the AC problem, and the problem with the hesitation and rough idle. Today, I finally get a call. The guy tells me "Well we sent it to our drivability department and we are thinking its your motor mounts." ........ motor mounts? ... :wtf:
Is it just me, or is that the equivalent of an ASE tech telling you that you have to have your radio on to put the car in reverse. OK I can understand maybe it doesn't help avoid vibrations, but come on, its not gonna cause the car to dip erratically in idle and run like is it? I'm no expert, but I call :bs: For as long as I've had the car, no mechanic has told me it needed new motor mounts, and I don't recall the engine ever vibrating badly.
Well now I have to wait for them to send it off to the A/C department and HOPEFULLY fix that without telling me its my seatbuckle broken or anteanna stuck. $65 diagnostic fee per problem...just to tell me its the motor mounts and possibly transmission mount...
Wow, that's shafty dude. I would be P.O.'d too. Motor mounts don't make the car hesitate and stumble.
And I lied...the problem did not go away completely. It's better but still there. I am going to swap out another upper intake and throttle body to see if that does anything. Sounds strange but that actually did help on my old '88 XR7. If the problem exists after that...then I have no frickin' clue what it could be. I'm starting to lean toward the O2 sensors more, even though everything is telling me it's emissions related. I will also snag some TAB/TAD parts at the boneyard next week and try swapping those in. What a pain.
The unsolvable problem strikes again!! haha. Geez its not supposed to be this hard. :giggle: One of my shop manuals said that it could be caused by worn cam lobes? By the time this is done we may have completley restored cars!
I just want to pay the 65 bucks ( x's 2 cause I listed 2 problems :mad: ) and get my car back. Remind me never to go to a dealership again for car problems.
you know matt, i was just remembering something. A few years ago in va beach, a ford tech installed a "delay valve" which was placed in line with my egr to cure hesitation.
i still have this valve but its up with my spare parts. Its a "rated" valve sort of, kind of a timing thing where the egr lights off too early or too late and things like delay happen.
hummm , maybe you could read up on egr troublehooting tips. Thunderchicken sent me a world of info on em and they seem pretty logical when you stew on it for a while.
got a fax?
Can you clean/replace those screens? My '85 Cougar hesitates a good bit. Everything I've tried hasn't eliminated it.
if you can find em,, yeah. I dont have any ,, just tossed my old ones.
i installed a secondary filter up in the engine bay inline with my fuel feed line.
I replaced my injectors with some from Advance ($100) and it cured my hesitation problem. My hesitation symptoms were not that of the thread starter though . My car hesitated anytime you hit the gas, off idle was the worse. I believe it was due to contamination from leaving the inlet/outlet to the CFI open to the environment for a week (long story). That contamination also caused the check valve on my FP regulator to fail. After replacing the injectors, the car feels like it has 2 more cylinders. I got worried when I took the old injectors out and the screens looked clean, but the proof is in the pudding.