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SOHC "hiccups" when accelerating..


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My 1989 SOHC has started bogging down for a quick second when I am hard on the accelerator but if I let off the gas some it stops & if I accelerate lightly it runs fine & doesn't do it. Not sure what could cause this but it is driving me nuts. It started shortly after I put the glasspack muffler on but idk if changing that could cause this issue. My dad checked the timing & it was too high now that he retarded the timing the problem seems even worse. Any help would be greatly appreciated. Thanks!

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9 hours ago, 89Chryslerati said:

My 1989 SOHC has started bogging down for a quick second when I am hard on the accelerator but if I let off the gas some it stops & if I accelerate lightly it runs fine & doesn't do it. Not sure what could cause this but it is driving me nuts. It started shortly after I put the glasspack muffler on but idk if changing that could cause this issue. My dad checked the timing & it was too high now that he retarded the timing the problem seems even worse. Any help would be greatly appreciated. Thanks!

The engine is going into overboots which causes the ignition and fuel delivery to be cut off momentary, at wide open throttle .

The vacuum/pressure line to the wastegate is broken at some point. Begin checking the line from the wastegate diaphragm back toward the wastegate control

solenoid.  It is one of those small hard, black plastic lines that run behind the valve cover, along side of the fuel rail. Be careful, they break easily.  fullsizeoutput_1511.thumb.jpeg.3e48d222532a530d08af336eb0ab2b78.jpeg

 

 

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Found a broken end on one vacuum line & found this little guy hanging down near the turbo & cannot for the life of me find where it goes! Sorry for the crappy pic best I could get of it but it's the line with the white plastic circle thing near the end.

20180719_134114.jpg

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Nevermind found it was a line I blocked off because I didn't see a line anywhere. Hooked it up & now my hvac blows where I tell it to instead of only on the windshield. Sadly, my turbo is nowhere near as functional as it was with that line off for some reason..

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8 hours ago, 89Chryslerati said:

Nevermind found it was a line I blocked off because I didn't see a line anywhere. Hooked it up & now my hvac blows where I tell it to instead of only on the windshield. Sadly, my turbo is nowhere near as functional as it was with that line off for some reason..

So, you are telling us that   "SOHC "hiccups" when accelerating.."   now this is no longer occurring? Then you have resolved your problem, RIGHT? 

There is no doubt that you will feel less turbo boost, therefore less acceleration performance with the system operating as designed.

This car is not a Dodge Daytona Shelby with boost regulated for high performance, it was supposed to be a luxury automobile meant for the affluent person in 1989, who could afford to purchase it for around $33,500 and use it as such.  We, who own them now, are mostly not so well endowed.

There are others here who will gladly assist you with increasing the boost pressure and in turn assist you with making your connecting rod bearings look like those in the following pictures.

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DSCN1056.thumb.JPG.51f9e6636c67aada1cd0c97e5b5602a7.JPG

DSCN1057.thumb.JPG.6e39b249e5f505f1ae3d3caf658f6d8c.JPG

This is what happens if too much 'performance' is applied to a tired 30 year old engine. So, be content with the performance it has or you could pull the engine and rebuild it so it can handle the added power. 

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While this is a possibility, with the correct attention to the correct parts, and a good tune, you can EASILY make over 200whp RELIABLY.

 

My Shelby Z had ~200k miles on it when I got it. The head had a bad valve guide or something that caused #3 exhaust port to be 1/2 clogged with a carbon plug! We slapped a stock rebuilt head on it, I checked the bearings, put a crank scraper in, an oil cooler, associated bolt-on performance parts with a good tune and proceeded to beat the living crap out of it for the next 6-7 YEARS. I *finally* popped the head gasket, which prompted me to take the engine down a bit further. After all of that abuse, really, I could have plopped a head gasket back on it and sent it! Yeah, it was showing some wear, but not bad.

 

The point here is, if you do what is needed to make sure everything is in good shape and you use a good tune, damage to the engine should NOT occur.

 

I will say that there's too many people out there that won't at least check the bearings before throwing power at an older engine and they do run into severe mechanical failure.

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1 hour ago, Reaper1 said:

I will say that there's too many people out there that won't at least check the bearings before throwing power at an older engine and they do run into severe mechanical failure.

 

You are right Reaper1, most people do not. 

One of the critically weak points with the 8 valve 2.2L engines put into the TC was that with the forged crankshaft, the connecting rod bearings would wear down to a dangerous point during normal engine life. Having been with TC America since 1995, I have been asked by many owners "What is that strange rattling sound in my engine when I rev the engine while standing still?" I have told them that the connecting rod bearings are worn and suggested replacing them ASAP. Some of those people did not make it back home from the TC National Convention before bearing failure. 

I talk about my engine's longevity, with 286 K miles on it now. I will assure everyone, that I have replaced the entire set of connecting rod bearings in that engine years ago. Checking this condition is quite easy!

When you go to start your engine after the car has sat unused for a few days, be sure that there are no distracting sounds around, like your wife yakking to you as you prepare to drive her to the shopping center. When you turn the key to start the engine, LISTEN!  If you hear that rumble, rattling sound prior to the oil pressure coming up, you likely have some loose, worn connecting rod bearings. It is time to think about what you will do next.

My warning to 89Chryslerati regarding his engine was just that. We all know how nice it feels when we squeeze as much boost as we can into the engine. I have driven several cars where the line to the wastegate diaphragm was broken. If you work the throttle the right way, you can drive the car quite well this way until you hit the boost limit of the MAP sensor.

 

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Reaper where can you find performance parts? They seem to be hard to find for these engines. Are there better bearings available or do they just need to be replaced? I was told my engine has about 80k miles but with the odometer failing at 7,800 miles who really knows but it runs excellent so far only thing I had to do was the timing belt when it broke.

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Hemi, I wonder if the bearing issues are related to how often the car is used (or not as it were) and the film strength of the oil left on the crank? It seems the other TII cars don't suffer from this nearly as much. Same engine, but hooked to a 5-speed.

 

89Chryslerati, check with:

www.turbosunleashed.com

www.fwdperformance.com

 

and check out:

www.turbo-mopar.com

www.turbododge.com

 

You have the same TII engine found in the Dodge Shelby cars (NOT the numbered cars!) and all of the performance and tuning is applicable.

 

I hope that helps!

 

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