Check/replace evap solenoid? [update]

[DbqJoe]

Im going to check the coils tomorrow with a multimeter to see if they are the root of my bucking back and forth at low speed uphill. I will be getting plugs and wires replaced anyway, but have a feeling one of the coils might be down. Either way it should be an easy procedure (I hope) to check it.

However I've also been getting evap error codes. First was a P0442, and a few days ago it came up as a P0440. Also the gas cap check error is on the DIC. Before I take it to the shop to have it looked at, I wonder if I can check the evap solenoid with a multimeter to see if that too is working or not? I noticed this thread: viewtopic.php?f=18&t=20864&hilit=solenoid and thats the first time I've seen where that solenoid is. Is the line thats supposed to connect to it via a U-tube the vacuum line as well?

Lastly it could be the cannister. But where exactly is that located, and is it hard to remove/replace? I'm looking thru my Haynes book but it doesnt really cover it in detail, the 2000 Bonnevilles in that book seem to be an afterthought, unless models before 2000 use the same locations for some things.

[LeSabre in Buffalo]

I have no idea where the canister is on a 00+. Mine's in the driver's fenderwell. The rubber hoses going to the evap solenoids were dry-rotted and failing. Replacing them with 50 cents of vacuum hose fixed my evap CEL.

[Archon]

The canister is under the car, roughly under the back seat. It's a black or gray rectangular box. If the evap. solenoid is the problem, it's likely to be a mechanical rather than electrical problem. So, checking the resistance probably wouldn't help much.

If you haven't already, clean off any rust that has formed on the gas filler tube and lube the surface with some silicone, or dielectric grease. Check the evap lines, as Lesabre in Buffalo suggested, too. The canister isn't likely to be the problem unless there is some physical damage to it. While it isn't unheard of to have the solenoid go bad, a more likely suspect it the evaporative vent valve not sealing properly. That is located by the back wheel.

[DbqJoe]

Ok well I'll just leave it up to the tech to look at the canister/lines. Is there any way to tell if it is a mechanical issue with the solenoid, i.e. how can I tell that its working properly? And is removal/replacement easy if it needs to be done?

[LeSabre in Buffalo]

A person with a high-end scan tool should have the ability to make the solenoid trigger.

I'd also get a smoke test done to see if there's a broken evap line somewhere.

[golfyeti]

Im going to check the coils tomorrow with a multimeter to see if they are the root of my bucking back and forth at low speed uphill. .

Check your front engine mount for wear/tears -- the tear can be underneath it out of sight. Low-engine-torque bucking like you described has often been the symptom of engine rocking due to a torn front motor mount - an increasingly common issue.

You can test your mount by checking to see if your engine lifts a bit when applying gas while holding your other foot in on the brake. If the mount is really bad you can also feel a thud when suddenly letting off from a hard accelearion as the engine will slam back down on the frame without the usual cushioning of a more solid mount.

Check this forum for posts about the hockey pucks and rubber bushing mod. Works great.

[00Beast]

The mount won't cause "bucking" while in motion unless he's getting on and off the throttle. Have you replaced the plugs and wires yet, and has that caused the issue?

[DbqJoe]

sorry for the late reply. I filled up the car with gas (always 91 premium), made sure the cap was past 3 clicks and secure (also cleaned up the cap a little bit). The SES light went away by itself. However a few days ago it came back. This time its the P0442 code again.

I just checked the coils. 1-4, and 2-5 both came back at 5.35. 3-6 came back as 5.36. I havent checked primaries yet. I also noticed a rather strong scent of fuel coming from the engine bay. I turned the car over to make sure I reconneced the wires to the coils correctly, and I turned it off. As I was about to close the hood, the scent of fuel was fairly present. So it seems the gas cap is fine, must be a vacuum line, or something else. I dont know if these are connected with the bucking problem at low rpm (posted another thread about that a while ago). I already changed the front transmission mount but that didnt really help things.

I was hoping a coil would be bad, thats an easy fix for me. But I've got an appointment setup next week for a complete tune up. New plugs/wires and will have them look at the evap stuff.

[00Beast]

Could the schrader valve on the rail be leaking? Mine was, and it had a super strong fuel smell at idle while in the car. Tightened the valve with a tool like you would use in the stem of a tire and have had no issues since. I didn't have any codes, but I'd check that for your fuel smell.

[DbqJoe]

Took the car into the shop last Friday. Told them about the evap stuff, as well as the hesitation at 1500rpm on inclines. Turns out the solenoid was indeed shot, as was the fuel tank vent valve (was that the possible source of the gas order in the engine bay?). A smoke test was performed and the evap issues have been seemingly solved. I also told them to replace plugs/wires (not cheap) as well as an oil change. I also told them to replaced the oil pressure sender unit since they were going to change oil, and while I got screwed on the sender/labor charge, for the 1st time in I dont know how many years I actually have a working oil pressure gauge.

However the hesitation/chugging at 1500rpm on inclines has not been resolved at all. I was really hoping new plugs/wires would fixed the *dang* thing. I think perhaps they might have been confused and thought the evap errors and the chugging were related, but unless someone says otherwise I think its just a coincidence. So perhaps they thought fixing the evap would cure the hesitation, but it has not.

I noticed on the checklist of things that were done, that the tech wrote down that the MAF looked "like a junk yard part" whatever that means. 5 years ago, barely a month after I bought this car, the MAF did go out and I was stranded. Had to have the car towed to the dealership, and they replaced it which was not cheap. I dont know what "looks like a junk yard part" even means. Does that mean its not working or what?

Im taking the car back tomorrow to have them look at it again. I didnt have a chance to talk to the tech that worked on my car last time as he was working on someone elses and I had to go in a hurry. But hopefully he'll be in tomorrow morning, and we can sort this thing out. Its driving me crazy. I think Im going to check coils one more time just for the hell of it.

[SLEking]

give your ignition coil module a try for *shoot* and giggles

[DbqJoe]

I wouldnt know what do it. Isnt ICM testing much more complicated? All I have is a $20 multimeter to play with.

Also if it is the MAF, is it safe to disconnect the sensor and drive it around to see how it reacts? I read a post somewhere on here while searching and someone said they disconnected the wire and whatever problem they narrowed it down to the MAF went away. How long could I disable it?

[01bonneSC]

Chugging is a trans problem. Torque Converter Clutch solenoid.

If you mash the gas does it go away?

[DbqJoe]

Well I suppose. When the surging/chugging whatever we wanna call it appears, I'll press the gas pedal down a bit to get above 2000rpm or so and that seems to do it. Sometimes I will let go of the gas, it'll go away, then resume cruising speed. However sometimes when I do this I feel a pretty bad shudder before resuming cruising speed.

It happens seemingly only on inclines. Whether its 35mph @ 1500rpm, or 60mph @ 1500rpm.

I hope its not the TCC solenoid. Wonder how much thats gonna cost. Thing is, I need to find out for sure it is before I spend more money on it. Would a shop be able to test it, or would it have to be replaced first to find out if that is indeed the problem. Transmission issues is one thing I really dont need in my life right now.

Im going to grab my video camera, and hopefully it'll pick up the sound of the problem Im having. I'll post it soon.

edit: Btw, anyone know where I can get multimeter leads (I have the Actron from AAP) that can fit inside the primary sockets on the coil? The metal probe doesnt fit, the socket is too narrow.

[SLEking]

kinda sounds like the MAF. when my car chugged always at stops and really at randon speeds, hitting the gas would solve the problem. i finally figured out it was the problem. when he says "surging" that really draws me closer to that diagnosis because right after the car chugged, it would surge forward for a sec, then repeat all over. Pull the connector on your mass air flow and see if your car runs decent. make sure you pull your intake air temp connector too or the car wont start without giving it gas. (thats how mine was anyway)

[DbqJoe]

I read up on more on the TCC. It seems one common sign is the engine stalling at a stop or something. Thats not whats going on. The car seems to run fine crusing, or even giving it some power. The thing about letting go of the gas after giving it some power after the surging deal is hard to describe. It just feels sloppy.

Is the connector the MAF the one that snaps on top (2 wires into an adapter), of what I assume the tube like thing between the supercharger box and engine? Also where can I find the intake air temp connector? A picture of the engine bay with a crude MS paint arrows would be much appreciated. Dont wanna unplug the wrong connector obviously. If I do disconnected the MAF connector, is there any danger? I.e how long can I run it for, do I have to drive it conservatively? Also can I unplug the IAT and leave the MAF in to see isolate the IAT to see if thats the culprit, or would it not be the cause of my surging?

edit: Took some pics. I looked at my Haynes but it doesnt really go into detail. It lists the procedure on how to remove/replace a MAF, but it doesnt actually show what connector to unplug.



Again, if someone can paint some simple arrows as to which is which I'd greatly appreciate. Im genuinely curious as to how the car will perform with it disconnected. If the problem disappears, that would be great news (well I'd have to have it fixed, and the last time a MAF went out it wasnt cheap), and I'd finally know what the most likely culprit is.

edit again!: Is the connector on top of the rubber air tube thing the IAT? See viewtopic.php?f=18&t=19538&hilit=IAT+sensor

[DbqJoe]

Tired of adding edits.

Ok, read the Haynes a bit more clearer. I'm reasonably sure that black thing (with the ABC wire markings) is the MAF. And the plug on top of of the rubber elbow hosing is the IAT. I'm going to let my engine cool down a bit before unplugging both, then I will take it on a test run (and maybe to McDonalds or Culvers, because I havent eaten anything yet and Im starving).

Just wanna make sure, by disconnecting both, is there any short term risk? I.e. can I drive for 20 minutes without something going awry by having them unplugged. Dont want the car to die on me while Im going down the main street.

[01bonneSC]

ABC one is your MAF, the one on the tube with 2 wires is intake air temp sensor.

IIRC, start car, unplug MAF, if engine speed changes, MAF is good. If there is no change the MAF is bad.

Im still leaning towards TCC, I have the exact symptoms you are describing, uphill, same RPM. my MAF is new and it still does it.

Your torque converter isnt unlocking to when you go uphills like it should when engine senses a load. It unlocks when trans downshifts when you mash the throttle, then chugging goes away.

[DbqJoe]

Yeah thought so. I unplugged both, drove it for about half a mile or so. Just up the street where the surging usually kicks in. It didnt help. Same issue, and without the MAF/IAT plugged in, ran slightly worse. I didnt push it too hard though. Pulled over to a parking lot, turned the engine off, replugged them in.

I have to read up more on torque converters and such. It runs fine when I put the RPM exactly at 1500 on a level road at crusing speed. Guess that explains a lot of it. Man, I really hope its not the TCC. Thats gonna cost a fortune (at least a grand right?). Would I have to take the car then to a transmission shop or would a general mechanics shop be able to look at it? Is it possible to test the issue before actually changing anything, or would it have to be replaced and hope that it solves the issue?

The one thing I really want is to narrow down the problem. Dont want to spend a fortune on transmission repair only to find out it wasnt the culprit. Im going to have the ICM tested. Its possible the coils are good, but perhaps something in the ICM isnt sending the proper power to one of them?

I did some more reading about, could it be a bad O2 sensor? That too had to be replaced 5 years ago (left me stranded, as I recall o2 sensor and MAF were both replaced). Maybe its on its way out.

Lastly, could it be possible that the rear trans and engine mounts need replacing? I already did the front mount, and that didnt improve things, but the old mount was pretty torn. I do think the engine moves a bit too much for my liking when shifting gears. Can the other 3 mounts be visually inspected for damage without having to actually take em out? I know the rear trans mount is apparently a real PITA to replace, and I imagine labor costs alone would be a lot in order to have a go at the engine mounts.

Oh well guess I'll find out soon enough. Had lunch, gonna take a nap, then Im off to the shop. God, I hate cars sometimes.

[SLEking]

your cars doing all this surging and pulling no codes. that sucks lol i dont know if it would help but if its anything like my camaro some codes wont cause the ses light to come on. i would put it on a tech 2 and see if it will pull anything up for you. for these cars only having 260 horsepower or so their seems to be a lot of trans problems. you wouldnt think the amount of horsepower and torque on these cars would hurt the transmission so significantly. any shop can look at a problem. its just who do you trust to rip your kids internals apart and put them back together correctly and in proper order.