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Dave's Winter 88 Behaving Badly


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4 hours ago, Padgett said:

Can check the TPS (throttle position sensor) on the car. At idle should be .38-.42v. At WOT "over 4v". Should see a linear move between.

Will run an ED01 test the next time I take it out.

The bucking is much less now, but my goal is to make it run like it should.

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An equafire V6 should be both balanced and very smooth at all speeds above 600 rpm. I prefer a 6 with a 3.25" to 3.5" stroke in the 3-4 liter range.

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Just to bring everyone up to speed, I believe that the car is pretty much back to what it was. There is still an occasional "hiccup" but nothing like before. It idles great and I can accelerate to full speed with no issues. I have been monitoring the TPS and it goes from .38 all the way to 3.98 without a hitch. 

 Things replaced were; Coil Pack/Ignition Module [3 different ones 2 Delco, 1 Magnavox], Spark Plug wires, EGR [known good working one], Mass Air Flow sensor. I also cleaned all the ground wires [behind the battery, radiator area, as well as the ground and positive leads on the cable to the battery and the battery itself. I checked the 02 sensor and saw that it was working through the CRT.

I think in the final analysis it could have been bad fuel that had to work its way through the system which is why I've decided to do the spark plugs and fuel filter. I have them on hand so I think it is prudent to do so.

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Thanks for letting us know. The problem could have been as simple as some water in the gas. The good news is it seems to be fixed.

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Just got back from a 270 mile round trip running appointments. Not a single issue no bucking or anything. I think I will chalk this up to bad gas as all the symptoms/issues slowly went away. 

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On 12/29/2021 at 3:08 PM, DAVES89 said:

Just got back from a 270 mile round trip running appointments. Not a single issue no bucking or anything. I think I will chalk this up to bad gas as all the symptoms/issues slowly went away. 

Maybe it wasn't bad gas after all. I was talking to Bob a couple of days ago and I mentioned I have this habit of filling the car as full as possible [way past the clicks of the gas pumps]. Maybe I had so much extra gas that it got into the charcoal filter and caused my problem. At any rate I am a number of fills into it and even my wife says the car drives like it should. 

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  • 2 weeks later...

I don't know if Dave is going to post or not, but I am going to relate what we discovered today after he informed me the car refused to start yesterday. When I stopped by, we of course cranked the engine over and it gave every indication it was attempting to start. We installed a spark checker on each of the three coils (Delco), and it proved to have good reliable spark on all three. When cranking the engine over, it would buck and backfire through the intake, but just wouldn't maintain rpm and would die if the key was released. We pulled the line from the fuel pressure regulator at Daves suggestion and it had liquid fuel present, a sort of "ah ha" moment. The fuel pressure appeared to respond normally when we started this thread, but like anything you can't quite put your finger on, it did act a little strangely. Honestly, I put some of that down to the unknown accuracy of the gauge (Snap On), but it proved to be very good and stable. Of course Dave had another pressure regulator on hand. After the new regulator was installed, we also reconnected the fuel pressure gauge and cranked the engine with the vacuum nipple open on the fuel regulator. We still got the coughing back with occasional puffs of smoke from anything connected to the intake, including the small vacuum line to the fuel regulator. The fuel pressure would actually spike up to 50psi or so as it was seeing the coughing back as positive pressure in the intake. We tried a couple squirts of ether in the intake and it gradually would improve in the ability to run. With the throttle held slightly open it eventually started but ran terribly, but as we finally got some heat in the engine, and a couple of false starts and then quit, it gradually ran better and it would idle on its own.  

 

My guess at the time is the leaking regulator had badly fouled the spark plugs, brought on by the recent cold weather. Thinking about it now, is it possible the backfiring is what perforated the fuel regulator diaphragm, or the reverse? It sounded for all the world like an older V8 that had the distributor installed 180deg out. We took it for a test run on the Interstate with me chasing and it definitely scoots along pretty well. Dave reported it still has a bit of a bobble around 4k rpm under power but then cleans up and accelerates. I believe it is going to get new spark plugs tomorrow just to eliminate that last ignition item from the list. Maybe it will also help the less than normal fuel mileage? 

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Not saying it's not possible but I don't recall fuel fouled spark plugs ever causing backfiring through the intake. My experience is a fouled spark plug would just cause a miss or a dead cylinder. It sounds like something is causing a plug(s) to fire when an intake valve is open. As you say, like when a distributor is 180 degrees out but I don't see how a crank trigger ignition could do that. It's almost as if there is some crossfiring going on between spark plug wires. 

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Agree that something is hiding. Pretty much all of the ignition system has been replaced, some more than once. It runs pretty well once running so it is a bit of a puzzle. The only place where ignition timing is determined is at the crank sensor, which sends the info to the ECM, and then back to the ICM. Starting is handled more directly from the CPS to the ICM. Maybe a sheared key in the balancer to crank ? 

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There is another ignition module on the '88/89s. It's located on the column. It was replaced by the previous owner and left with me. I did have a no start issue some time ago and Kendall quickly diagnosed it so we took the replaced one out and put the "old" one back in. Kendall was sure it was good as he ran some test which escapes me. However it always started after that first all the time until lately.

I have decided to give up on the car. I put on about 15,000 miles [mostly business] and as I only paid $1000.00 for it [Silver award winner] it owes me nothing and I don't want to run the risk of getting stranded by the side of the road. That's almost funny as the Red has over 300,000 miles and that will be the new daily driver. As the Red is in Texas I will be driving the 'vert down to get it and leave the 'vert there. And yes until I leave for Texas the 'vert is the daily driver. 

 That's life and sometimes hard choices have to be made.

 So the car will sit until spring in the driveway until I get warm enough weather to swap some parts that are nicer then what I have on the Red and either 2seater [or his sons] gets it or it goes out to Gibsons. 

I already like the additional room in the garage.

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Just to be precise that is the start SWITCH. It has no electronics but is a frequent failure  (no crank) point.

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3 hours ago, DAVES89 said:

That's life and sometimes hard choices have to be made.

That is the way I view my Reatta. I really enjoy it but if something major happened that was expensive to fix (like a transmission failure) I would have to let it go or part it out.  

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This thread has got really long and I've lost track. Has the crankshaft position sensor been replaced?

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2 hours ago, Ronnie said:

This thread has got really long and I've lost track. Has the crankshaft position sensor been replaced?

I don't think so, but I could be wrong. It did get timing chain set and cam sensor magnet a while back. Hopefully Dave will set us straight. 

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The situation with the backfiring through the intake bugs me and I wanted to find out what might cause it. I was reading through the FSM this morning to try to figure it out.

 

The crank sensor is like two sensors in one that send two separate signals to the ICM to determine which cylinder should fire at the correct time in relation to the position of the crankshaft.  The first screenshot below, from FSM section 6E3-C4-2, indicates that BOTH signals from the crank sensor must be present for the ICM to know when to fire the correct ignition coil.

 

The next screenshot indicates that the engine can continue to run when only the 18X signal is present even if the 3X signal is not present. It also says the engine won't start without both the 3X and 18X signals being sent to the ICM. However, it doesn't say the engine won't try to run without both signals.

 

Here is what I'm thinking might be happening that would cause the engine to backfire through the intake and not start. It is the only explanation I have for the backfire and it is only an educated guess... I think half the crank sensor might be bad and it is only sending one of the signals to the ICM when the backfiring occurs. It's possible the ICM is getting a signal to fire, maybe from the 18X signal but it just doesn't know when to fire.   If the ICM fired the coils at the wrong time it could account for the engine backfiring through the intake and not starting.

 

Before junking the car because of this problem I think it would be worthwhile to replace the crank sensor and check the associated wiring that goes to the ICM as a last ditch effort to fix this problem. I would also remove the balancer and check the key in the crankshaft as 2seater suggested.  It might be a wild goose chase but there is a chance it might save the car from the scrap yard.

 

If you could catch it when it's backfiring and not starting you could do the  ICM & Crank Position Sensor Troubleshooting  tests and see if that would tell you something.

 

FSM 6E3-C4-2     (C3I=Computer Controlled Coil Ignition)

Screenshot CPS pulses-1.png

 

FSM 6E3-C4-5

Screenshot CPS pulses-2.png

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I am of similar mind. The CPS is the one common item in the ignition sequence that is always in play. I learned when my car failed a CPS that the failure mode was not what we or the FSM said should happen. It didn’t stay failed as it normally would, much like the leaking fuel pressure regulator that still worked on this car. It definitely seeped fuel, but must have sealed well enough under some conditions to give a false indication.

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I don't believe it is the key in the harmonic balancer, but have thought for some time that the CPS could be my culprit. I have always said that if the car is unmolested [and this one is] the problem is not in the wiring but in an end item [silver box, ignition module, plug wires, Mass Air Flow senso]. 

 I go over to Kendall's Monday night to shoot pool and we can talk about it then.

Thinking with all the support I have been getting, that I will just leave it parked and take it up later this spring after my return from Texas. It really is a nice car.

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Believe it or not with all the miles I have put on I have never replaced a crank sensor before. The Red's was replaced when I did the engine swap.  It looks like there is an 8mm bolt that you loosen and then the sensor can slide out. Also looks like it is a "reach up from the bottom" proposition. Is that correct.

 

BTW 2seater. That 10mm socket and little bolt from the fuel regulator was laying in a bit of oil dry I have under my side of the garage, so all is found.

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8 minutes ago, DAVES89 said:

Believe it or not with all the miles I have put on I have never replaced a crank sensor before. The Red's was replaced when I did the engine swap.  It looks like there is an 8mm bolt that you loosen and then the sensor can slide out. Also looks like it is a "reach up from the bottom" proposition. Is that correct.

 

BTW 2seater. That 10mm socket and little bolt from the fuel regulator was laying in a bit of oil dry I have under my side of the garage, so all is found.

Very glad the missing bits have been found.

 

I don't believe the CPS can be removed without removing the balancer/damper first. The bolt squeezes the fingers of the mount together to hold the sensor once it is centered on the two shutter wheels inside the damper so they are all meshed together when installed. It may have been possible if the bracket that holds the sensor wasn't stuck on a locating dowel pin that sticks out from the front cover, but it is. It may be possible to slide the sensor out of the holder/bracket if the damper is pulled out an inch or so, but that still requires removing the serpentine belt and the crank bolt. Being an 88 it shouldn't have that little damper shock in the way.

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