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For those following along , Please NOTE,
Posting close up pictures of the engine is always a great idea in your first request for assistance.
Even though you might not think so at the time.
A lot of info is added to the mix to make an accurate assessment and guess on how to proceed.
Lots of times clues are present but they cant be seen unless they are posted
Posting the picture of the knock sensor connector wire connector tells me all I need to know on what the condition of your engine is in.
At this point your car is talking to you,
its telling you that its time for my intake refresh.
My suggestion ,
dont do any more trouble shooting till this task has been completed.
ready for an intake refresh and soon to tell it also needs head gaskets.
Intake refresh and head gaskets job almost finished
Are head gaskets commonly needed at 80k miles on a car with no symptoms of such a failure?
Originally Posted by Mrmerlin
For those following along , Please NOTE,
Posting close up pictures of the engine is always a great idea in your first request for assistance.
Even though you might not think so at the time.
A lot of info is added to the mix to make an accurate assessment and guess on how to proceed.
Lots of times clues are present but they cant be seen unless they are posted
Posting the picture of the knock sensor connector wire connector tells me all I need to know on what the condition of your engine is in.
At this point your car is talking to you,
its telling you that its time for my intake refresh.
My suggestion ,
dont do any more trouble shooting till this task has been completed.
ready for an intake refresh and soon to tell it also needs head gaskets.
Intake refresh and head gaskets job almost finished
this 88 I am working on was not taken care of and the PO had just water in the coolant system,
so this ruined the HGs as well as time.
If good coolant is used and changed on time the HGs last a long time,
but think about it these parts are getting to be 30 years old.
The 16 valve engines suffer more from head gasket issues, as they are older
BUT all of these engines will need this service at some time in the future
Posting the picture of the knock sensor connector wire connector tells me all I need to know on what the condition of your engine is in.
No it doesn't, don't go throwing the baby out with the bathwater here.
My knock sensor connector in my 87 didn't look any better & the car runs perfect. Sure I'll be pulling the intake sooner than later, I'm not about to do it in August with months of driving to do - which is what the OP would like to do: drive the car.
The 3-pin connector is still available: https://www.ebay.com/itm/391537864264
I'm sure one of our vendors can get a better price.
The way this forum is going, every small problem turns into a complete engine rebuilt after a dozen posts.
No it doesn't, don't go throwing the baby out with the bathwater here.
My knock sensor connector in my 87 didn't look any better & the car runs perfect. Sure I'll be pulling the intake sooner than later, I'm not about to do it in August with months of driving to do - which is what the OP would like to do: drive the car.
The 3-pin connector is still available: https://www.ebay.com/itm/391537864264
I'm sure one of our vendors can get a better price.
The way this forum is going, every small problem turns into a complete engine rebuilt after a dozen posts.
You're right if that is the OP's intention. Driving season is not a factor here in south Louisiana because we basically have a 12 month driving season so I tend to forget about cooler climates.
Decided to take it around the block and about 3-4 minutes into my short drive it suddenly died and did not start after maybe 10 tries to start. This is good! I can now hopefully reliably diagnose what is causing it.
Pushed it home the block and a half (heavy car!) and ascertained there is no current going to fuel pump. Forgot to see if I had tach bounce while cranking... I'd like someone to tell me if the clicking noise that you can hear in the video when the key goes to ON, just before I crank, if that is the injectors clicking or is there another normal source of clicking in the engine compartment that would normally make this noise. I have a noid light but didn't attach it.
So knowing I have spark and fuel pressure (by jumpering 30-87 at the FP relay) I try to start it and it runs but very roughly if I play with the accelerator but doesn't stay running; very rough and wants to die
Thoughts...??
Luis,
You are doing great at giving everyone the clues they need...
Cheers,
Dave
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That's what he said in post #9, and it's a typical feeling around these parts. Putting off non-mission critical fixes until winter.
Besides that, I enjoy finding root causes & fixing them. Sure many random annoying issue can be fixed by yanking the mill and replacing everything. Some of us like to dig in and actually find the problem & fix it.
Intermittent issues are fun, and I could see whatever is causing this issues having nothing to do with an intake refresh.....after going through all that work & the problem still exists.
That's what he said in post #9, and it's a typical feeling around these parts. Putting off non-mission critical fixes until winter.
Besides that, I enjoy finding root causes & fixing them. Sure many random annoying issue can be fixed by yanking the mill and replacing everything. Some of us like to dig in and actually find the problem & fix it.
Intermittent issues are fun, and I could see whatever is causing this issues having nothing to do with an intake refresh.....after going through all that work & the problem still exists.
I welcome ALL suggestions and collective knowledge being offered so I was reluctant to poo-poo any suggestions but you hit it right on the head. It's driving season here and although I'm a pretty good wrench and could do an intake refresh in 1/2 a weekend (I think...) I really want to a) Diagnose what is causing this and b) fix what is needed to be fixed to get the car going. However I need to balance that with doing as much as it makes sense "while I'm in there" . But I am comfortable pulling the intake again over the winter months to beautify it. That's what winter is for.
Thank you all! Now can someone figure out why the car didn't start under the conditions I outlined...?? I will be replacing the CPS this week and eliminating that variable. What about the clicking on the video, is that the injectors --as in a bad LH...??
Anyone in Wisconsin with a spare LH that we can swap and try...??
I reached out to the MKE crew to see who's around when & what parts we have available before we start taking parts from the running cars. I only have the one in my 87 and I'm out of town this weekend. If this isn't resolved into next week, I'll see what I can do if the Milwaukee gang isn't available sooner.
Even if that ends up not being the issue, add to your winter to-do list an ECU rebuild. Better safe than sorry to have them gone over before they decide to fail.
I reached out to the MKE crew to see who's around when & what parts we have available before we start taking parts from the running cars. I only have the one in my 87 and I'm out of town this weekend. If this isn't resolved into next week, I'll see what I can do if the Milwaukee gang isn't available sooner.
Even if that ends up not being the issue, add to your winter to-do list an ECU rebuild. Better safe than sorry to have them gone over before they decide to fail.
Erik, thanks for the offer. Yeah, let’s wait until I get the CPS in there —I’ll try w/o pulling the intake , fix just the connector in the knock sensor and recover it with heat shrink along it’s length and then see what the car does before we go pulling LHs from folk’s cars.
I welcome ALL suggestions and collective knowledge being offered so I was reluctant to poo-poo any suggestions but you hit it right on the head. It's driving season here and although I'm a pretty good wrench and could do an intake refresh in 1/2 a weekend (I think...) I really want to a) Diagnose what is causing this and b) fix what is needed to be fixed to get the car going. However I need to balance that with doing as much as it makes sense "while I'm in there" . But I am comfortable pulling the intake again over the winter months to beautify it. That's what winter is for.
Thank you all! Now can someone figure out why the car didn't start under the conditions I outlined...?? I will be replacing the CPS this week and eliminating that variable. What about the clicking on the video, is that the injectors --as in a bad LH...??
Hi Luis,
Let me try to explain what is happening now that your LH has gone from failing to failed.
The clicking you hear on ignition (before startup) is the injectors clicking at a static rate. Basically the computer has lost the ability to control them and they fire on their own. The static rate seems to support around 500rpm. So when you jumper the fuel pump (the LH has lost communications with the ignition computer and therefore won't activate the fuel pump) you add fuel supply to a set of injectors that are firing at that static rate....so it starts and tries to idle around 500rpm or so...then the moment you touch the accelerator it dies because you have increased the air flow passed the amount of fuel being supplied by the static injector rate.
For what it worth, when a CPS fails, there is never spark or fuel. Basically without the signal from the CPS the EZK Ignition Computer won't activate, so neither will the LH. As I mentioned before that can be intermittent if there is fluid on the valley etc. but the symptoms are always the same.
If it were my S4 I would have called Jim Corenman last week.
Oh, when you are ready to do your Intake RnR this winter, check my website for "928 Specialists Kits" in the left menu, go there and look for Intake Kit for your S4, It is interactive, and you can pick and choose what you need and it will recalculate the cost for you on the fly. www.928gt.com, or just click any of my Sponsorship Banners at the top right on every page here.
Don't bother trying to re-sheath the knock sensors, if the connector and covering is that bad, the plastic insulation around the knock sensor is going to be in the same shape. Just plan on replacing them at some point.
From that video of your spark plug, it sounds like your injectors are clicking away when you turn on the key and continues until you turn the key off. That's a classic failure of the LH. If you've got someone around with an 87+, put that LH in their car and see if it does the same thing (it will) or swap a good rebuilt one in your car. My bet is it starts right up and runs. Keep us updated.
Edited to add, about the CPS, DR is generally correct that it's a go/no go most times. But there are others. Had a 951 that wouldn't run past 3krpm and new ones fixed it. Had a call from a Rennlister the other day who's car was doing the same thing, no go past 3krpm. New CPS fixed that issue too.
Edited to add, about the CPS, DR is generally correct that it's a go/no go most times. But there are others. Had a 951 that wouldn't run past 3krpm and new ones fixed it. Had a call from a Rennlister the other day who's car was doing the same thing, no go past 3krpm. New CPS fixed that issue too.
Yeah I seen that too, vibration of the cracked connectors causing intermittent issues. I bet that would be more evident on those vibrating 4 bangers....LOL
08-07-2018, 09:33 AM
