[mkeith]

Does anyone know of a good way to check the hydraulic lifters on the 24V? The shop manual doesn't give much info about the lifters.

I'm trying to nail down a rough hot idle & intermittent 1223 code that occurs only at idle. It's been a problem on this car for quite some time. Ignition modules, coils, plugs, tbelt, pulleys, etc all fresh. Cam timing (with dyes) is spot on. No vacuum leaks & freshly serviced injectors. Recent O2 sensor as well. Passes emissions (no emissions testing at idle in TX) with flying colors.

The motor makes quite a ticking noise once it gets up to temperature, & I was thinking that one or more lifters might be stuck. However, a leakdown test revealed no such problem. Of course, I did the leakdown test with a cold engine since I'm also addressing some cooling system leaks. Even if I had the chance, I don't think I'm fast enough with these cars to remove everything necessary for a leakdown test & still have a hot motor.

Thanks in advance for any input.

 

[Del]

Check the ignition connections under the air filter box. Known on these particular cars to get very contaminated and cause these problems, including complete but intermittent ignition cutout. Had the same sort of problems, and when I cleaned (and used dielectric grease) on all the electrical connections under the hood the problems went away. The main culprits were those ignition multiconnectors for the modules under the filter box. That is a very bad location for contamination.

 

[goats]

1223 code

is listed as "lambda probe regulation faulty' or something like that, but in practice in my experience it means 'feedback from lambda sensor to motronic results in an out-of-range expected output set' --
Have you tried using some hydrocarbons (I like an unlit plumbers butane torch when the engine is hot) all around all vacuum / air lines, plenum, etc? from what you describe (ignoring the ticking sound) something is getting hot, expanding, then leaking would be my guess.
With the unlit butane torch and with butane flowing, shoot that unlit gas all around the engine compartment to see if you can detect a change in enging sound. On a cold engine, brake cleaner or carb cleaner works great, but if the engine is hot, you run the risk of flashing that stuff and singing your eyebrows!

As for the ticking, I presume oil pressure is generally good ? Have you pulled the covers off and looked at clearances?

 

[mkeith]

Connections for modules, coils, & injectors were cleaned when coils & modules were replaced. Grounds cleaned as well. Checked for vacuum leaks with mapp gas.

As I understand it, the 1223 code essentially means that the oxygen sensor is at the limit of its ability to adjust mixture, & the mixture is still out of tollerance. CE light resulting from the 1223 code goes away as soon as you blip the throttle.

Ticking sounds like lifter noise or an exhaust manifold leak. However, the car has all new manifold gaskets, & there was no signs of cracks in either of the manifolds. Either way, it's definitely not a bottom end noise, & oil pressure is fine.

Cam covers are off at the moment since I put the cam dies on it. I was not aware that there was any measureable clearance between the cam & the lifter on the 24V since it has hydraulic lifters. What should the clearance be?

 

[Alfisto Steve]

I would think with hydraulic lifters any measureable clearance would mean a clicking noise. I used to run a Rocket Olds 88 engine and if hydraulic lifter (tappet) didn't pump up FULLY it would tap tap away with engine running.

Can't test a 24v 164 engine running with covers off like I could with old Olds engine though can you!

 

[theduggerr1]

Did you ever sort out that ticking noise when the car gets hot? I have the same problem on a 95 LS. It's not triggering any codes for me yet, but this sounds spot on to me.

 

[mkeith]

Not yet. I got side-tracked with other work, but I'll be back on it some time next week. I did find that the rear manifold nuts were kinda loose. I'm going to replace those gaskets. That could be the cause of the ticking noise, but I don't think it has anything to do with the rest of the car's issues.

 

[junglejustice]

Hey Michael - how are ya!?

I would say that your 1223 issue is not a lifter problem, but if you want to get in to servicing them properly, give me a buzz; it would be nice to catch up anyway. You have to bang the plungers out of the followers, collapse them completely, open them up, clean them / pressure release them and re-assemble them!

For the record, these lifters do lose pressure when the motor starts working hard and when the oil gets thin; the power will even drop off on the dyno and come right back with fresh, cool oil - but that is not your problem here. Does the CEL come on at idle and then drop out with a bit of revs?

You have a small vacuum leak somewhere. Too much to type - buzz me!

Cheers, JvR
425.941.4747

 

[mkeith]

Hey Jon,

Good to hear from you. I'll give you a ring some time this weekend.

Yep, it's the classic CEL at hot idle that goes away as soon as you give it a little gas. Idle quality when hot is mediocre; not so bad on a cold motor.

I'm farily certain that I don't have a vacuum leak, but when you're certain of something, the best thing to do is double check it.

 

[Touringspider]

I have the exact same issue right now with the 95LS five speed daily driver (150k miles). I have ticking, and I have an extremely annoying and intermittent ignition cutout. Sometimes it is subtle and sometimes it is extremely violent where the car lurches. The CE light will come on but goes out if I LIFT OFF the throttle (the opposite of Michael's blipping). The car starts immediately and never threatens to stall, but there are times it is almost undriveable, and then it is OK or subtle enough to drive around.

I just took the car on a two day British/Euro car tour here in AZ, and there were times that the engine felt like it was running on 3 cylinders and would not respond to throttle, and then it would clear up. In fact, on one uphill stretch of I-17 by Flagstaff (Jason will be familiar with this) I could not go over 65 mph with my foot to the floor, and then it would suddenly clear up. Another time, I was barely able to make an uphill start from a traffic light since the engine would not rev over 3k, and then it suddenly shot me forward.

Fuel filter is new, submersible hoses in tank are new, entire vapor recovery system was just checked and cleaned, and there are no vacuum leaks that I or the shop can find.

However, I notice that if the car is parked there is no residual vacuum in the brake system (pedal is hard as a rock). Could this be a clue?????

 

[mkeith]

Touringspider, your problem sounds more like a faulty ignition module. My 94 displayed similar symptoms but not as bad. My modules had both been recently replaced, but my #4 coil was arching pretty bad. After replacing the #4 coil, I still had the problem, & swapping modules around made the problem go to the rear cylinder head. A new module resolved it.

My best guess is that there was some sort of feedback from the arching coil on #4 that somehow damaged its associated module.

 

[Touringspider]

So, how does one isolate which one (or more) ignition coils are bad? I suppose you could get a new one and swap each one out and stop when things get better, but if more than one is bad that won't work. Also, the back bank requires the intake coming off for access so running the car at that point is not practical.

I'm going to start by cleaning all the connections and using dielectric grease as Del said, and hope the simple fix does the trick...

 

[mkeith]

Well, I finally resolved all the problems listed in this thread & picked up a new problem in the process. So, I'll finally close this one out & start a new one.

Replacing the rear manifold gaskets got rid of the ticking. I also used new brass nuts & split lock washers to prevent them from backing off again.

The rough idle & code 1223 were resolved with a number of fixes. First off, the dog bone engine mount had poly bushings & was not properly adjusted. I replaced the big end with the stock piece & adjusted it. Secondly, as Jon suspected, I did have vacuum leaks. I put a smoke machine to the car, & I found that idle controler's internal seals had failed. Smoke poured out at the wire harness connector. The EGR valve also leaked internally. The smoke machine was a life saver here. I would have never though to look for vacuum leaks in those places. It also turned out that the injectors had not been serviced as I first thought.

These fixes got rid of the rough idle, but I was still getting the 1223 at idle. Luckily, I had service records going back to the begining on this car. One very old invoice had a note mentioning that the technician has tampered with the AFM in order to resolve a rough idle. So, I replaced the AFM with one from the owner's parts car, & the code went away.

However, now the car wants to stall whenever I let off the throttle when coming to a stop. It fires back up immediately, but, despite having put some miles on the car, the problem persists. The owner states that it was doing this sometimes before I started working on it, but he failed to mention it to me. Therefore, I'll start a new thread to address this issue.

Jon, I still owe you a phone call. Sorry I neglected to call. Things have been busy.