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Spark issue? Rough running, down low


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#1 TajMan

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Posted 10 December 2017 - 02:26 PM

Hey guys,
you could help me diagnose what is wrong with my new '89 Conquest Tsi I'm getting back on the road.

I bought it from a guy, he had taken the car as trade so he didn't know all about it.. 57K original miles, automatic. He changed the oil and put some plugs in and gas in the tank and a battery, got it started! I purchased it at this point, he said it still ran rough down low when cold sometimes, and ran smooth when it warmed up.

I got a bent front rim replaced and put tires on it. Replaced the fuel filter (and I have another I can replace again soon), and I changed the auto trans filter/pan gasket and a good 9qts worth of atf.
I replaced the cap/rotor, and spark plug wires. Got damage on the OEM front-mount IC welded enough for a temporary patch fix.
Between all of this, I had the engine at times feeling like it was running 100% smooth/proper.
Also somewhere in this installation of ignition stuff, it wasn't right anymore, like only running on 3 cylinders!

I've now tried two different full sets of ignition wires, 7mm Belden NAPA brand. I also pulled the plugs, and the guy I got the car from put in some new Champion plugs that seemed to be wrong for the car, the threaded section was much shorter than the AC Delco R42XLS plugs I just gapped/installed.
Even after all this, plug wires seated good, and letting engine warm up completely.. it's still not right now, like it's running on 3 cylinders, can't get it smooth. This is at lower RPM's, if I keep it to 4,000 rpm's and beyond things smooth out more, I can't tell if proper up top or if just revving high enough the miss can't be detected as bad.

I was getting a modified MPI intake manifold for later, custom EFI conversion/install... and I am also interested in electronic ignition conversion and ditching the distributor..
I was just hoping to drive this at my winter car now soon, first, and begin swap later. I had just assumed the low mile engine was good.

Can a clogged fuel injector or fuel problem with the stock TBI cause engine to miss or feel similar to an ignition problem with 1 cylinder?





#2 croquest87

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Posted 10 December 2017 - 04:04 PM

HI there   l would start w plugs out and compression test  injector plugs disconected ignition coil disconnected  throttle open wide during the test if all good let's move onto next  clean your tank  get rid of the cone inline filter before the pump/replace w wix metal fuel filter next replace main fuel filter in engine compartment next replace fuel injector conectors clean connections and new seals  and perform fuel injector leak test  there is a plug next to air can that you can run a wire from to the battery to turn the pump on while you look inside throttle body for leaks/drips.      leaks? Car will not run right  primary injector runs the engine alone until around 2500 rpms

#3 markhansenconquest

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Posted 10 December 2017 - 05:10 PM

u need to test your CTS ..O2 ,, TPS,, AIT sensers and back flush your 30 yr old injectors............ All those things talk to the ECU to control fuel mix................

Edited by markhansenconquest, 10 December 2017 - 05:10 PM.


#4 croquest87

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Posted 10 December 2017 - 05:59 PM

Don't guess it  test it and know what's up one thing at the time even though it may sound like a lot of work thats how you learn  post any questions you have people here will help you  good luck

#5 TajMan

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Posted 21 December 2017 - 12:28 PM

Thanks for the help, pointing me down the right directions.
I post, might seem a little newbish.. but I guess that's just in relation to the TBI system,
I've got a shop here in Salt Lake, I do all manner of work, If I can't do something I learn and teach myself.
The other '89 Conquest I owned 10 years ago.. I never had to do any work on its TBI system.

I was just waiting to post some results.
I've got the tank dropped now.... GOOD GOD.. it was baaad. Rust and crud and chunks and 'growth'
This has been a a multi-day cleaning process already, attempting. Local radiator shop wants over $120 to steam clean it or over $220 if they have to re-coat it also..
I feel like I'm going to get it good enough I can put new gas in and run it.. but it will probably keep breaking off rust chunks/sediment in the future, I'll have to check it again later to see. If I'm ever making a trip in the midwest somewhere closer to a part, or if I wanted to pay for shipping, I'd be interested in a different fuel tank from another car.

I can't believe it ran at all before! PO said he put new gas in the tank (probably $20), it was probably very very low almost empty with black saturated filth beforehand, the fuel that got drained out was pretty black.

Things going through my mind, I want to do some more checking/comparison between a Stealth Twin Turbo fuel tank I have (still on a '93 AWD parts car that's upside-down behind my shop lol).
I would not be opposed to cutting my Conquest floor up to move the access hole for the in-tank pump sending unit.. if I could get the 3/S tank to fit in the Starquest.. little chance. 1st problem is fuel fill was located on opposite sides of each car, so tank would have to be flipped around 180 degrees, little chance of mounting..

Edited by TajMan, 21 December 2017 - 12:29 PM.


#6 TajMan

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Posted 21 December 2017 - 12:44 PM

I had 2 gallons of 'carb dip' soaking solution inside the bottom of the tank soaking overnight, and I had a ton of screws and nuts I poured inside, sloshing all around trying to break up chunks.
After that was drained from tank and I fished out most of the screws/nuts with a magnet, flushed with dish detergent again,
and then it sat for hours with a pretty strong oxalic acid (wood bleach) soak! Dumped that out and filled with more hot water/dish detergent solution and sat overnight again (mild oxalic acid remaining I'm sure).
I'll flush it out more, and baking soda flush.. its cold outside just snowed a little here yesterday. Plumbing in areas frozen and I can't even get a hose outside to work..
Industrial area has its benefits and drawbacks.

Edited by TajMan, 21 December 2017 - 12:49 PM.


#7 speedyquest

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Posted 21 December 2017 - 02:13 PM

I really hope this doesn't come off as rude but if you own a shop wouldn't you also understand the benefit of do it right the first time? If you don't have the tools to clean the corrosion and re-coat the inside of the gas tank why not pay that other company to do it? $220.00 sounds like a fair price in my opinion.

Idk, just my thought. Take it with a grain of salt.

Edited by speedyquest, 21 December 2017 - 02:13 PM.

1987 Flatty Starion -- Widebody Conversion -- V-Mount Setup --  JDL Tubular Manifold  --  MX-6 Intake -- MS3-Pro -- AEM FPR  --  ARP head studs -- 3" hood exit exhaust -- Hahn Racecraft 16g --  Tial F38 Wastegate -- Tial Q Bov -- Short route piping -- 5 lug & LSD conversion -- Tubular Front End -- Manual Steering Rack Conversion -- Manual Brake Conversion -- Stack Digital Dash -- AEM UEGO -- D2 coilovers -- full GNT poly bushings & mounts -- four 8" rears -- car lightened significantly...  More to come!


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Build Thread --->  http://www.starquest...opic=143564&hl=


#8 TajMan

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Posted 21 December 2017 - 02:52 PM

I am speaking freely what my mind is thinking, evaluating as things progress,
and also have bigger long term plans that I do, while just trying to survive at the moment.
I do my own, through my personal struggles- I suffer from short term memory loss from traumatic brain injury, motorcycle accident almost 13 years ago, still taking care of my own and I have my self respect. No judgement needed where someone doesn't know.. and I know you said just your grain of salt.. you are polite.

It's just hard.. I coat my own gas tanks, multiple experiences with both Caswell epoxy gas tank sealer and KBS coatings.. This auto tank is big though, with big baffles inside.. honestly $2xx is a fair price but I don't even trust this company's ability to really remove crud and re-coat everywhere! "Good enough is good enough, what customer won't see won't hurt anyone" (is what I perceive they're thinking), I hold myself to a high standard.
Just speaking freely.. I haven't even had a chance to take a good look inside after most recent cleaning steps, yet.

#9 TajMan

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Posted 21 December 2017 - 05:00 PM

I'm in a state of disbelief right now..
Just did a compression check, I was all ready to do it before with plugs out, I just hadn't yet, I had convinced myself I was sure all was ok.. however. just checked and I seem to have zero compression on cyl #4 by the firewall!!!1

Tank is pretty horrible still, but i was ready to take it in and pay for a steam-clean, that would be a fair deal and I think most of the deposits come off clean underneath if you can get them loose.

I swear it was running at 100% at times in the past (from my perception, idling).. I'm just shocked that I have a dead cylinder.
Changes short-term plans for sure.

Edited by TajMan, 21 December 2017 - 05:01 PM.


#10 croquest87

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Posted 21 December 2017 - 07:08 PM

Man that sucks  l was just going to suggest  doing electrolysis  on your tank and 3 step por15 l did mine years ego and it's still perfect condition  all you need is a battery charger and some sodium carbonate and piece of rebar as sacrificial rod  works like a charm and will pull all the rust out even from baffles

#11 croquest87

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Posted 21 December 2017 - 07:18 PM

Re build it it can be done on low budget if you stay all stock

#12 croquest87

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Posted 21 December 2017 - 07:21 PM

Re build it it can be done on low budget if you stay all stock

#13 TajMan

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Posted 21 December 2017 - 09:25 PM

I'll be spending $1500+ at Engine Machine Service when I'm able to.
Wiseco pistons, Non jet valve head, ARP hardware, balance shaft delete, new bearings, all the goodies to make it a stout fresh block!

It's a bummer.. I just put used winter tires on it so that I could drive this season.

Is it possible for a valve to stick open? How do those factory jet valves work anyway?

#14 Hoosierquest

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Posted 21 December 2017 - 10:17 PM

Jet valves run off the intake rocker. Before dumping the money on a rebuild pull the valve cover at least.  Also do a leak down check.
<a href="http://s102.photobuc...t=100_2004.jpg" target="_blank"><img src="http://i102.photobuc...h_100_2004.jpg" border="0" class="linked-sig-image" /></a>

87, .030 over JE's, non jet head, small 16G. Delphi injectors.  Quest owner since 2000.

#15 croquest87

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Posted 22 December 2017 - 06:39 AM

If jet valves are suspected in this while you are at it spend around $20 and get jvek and eliminate them it's cheap and easy to do  they just screw right in also while at it l would replace all the valve stem seals it can be done w out taking cylinder head off w simple tool from auto parts  you will probably have $50 investment in all this  l guess it's worth the try  usually  when you pull jet valves on a suspected cylinder they look welded from overboosting or just simply stuck cause they are alot thinner in design than valves and get super hot my number 4 was melted and chunks from it destroyed my cylinder walls

#16 TajMan

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Posted 22 December 2017 - 06:43 PM

LOL
its exciting guys, I'm learning so much

the jet valves.. what a stupid engineering design.

I've got the rocker assembly off. All the jet valves feel like they operated the same, #4 out, it seems fine.
I guess It's not worth buying/waiting for/installing the jet valve delete kit when it won't do anything. I don't think the leak down tester will help much anyway..
I have ZERO compression while cranking with #4 spark plug hole plugged up.. I'm guessing either hole in piston or burned valve or serious leak in headgasket.

I guess time for more work to pull the head.
Everything looks real clean inside, 57K miles!

such a bummer, no wonder reason why the car sat for over 20 years, possibly.. Car has a replacement front bumper/hood/drivers fender from another car, I had previously assumed it was off the road from an old minor wreck that was never completely repaired since..

#17 croquest87

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Posted 22 December 2017 - 08:28 PM

Well it is what it is right? It's good to go through the engine fo piece of mind  good luck

#18 TajMan

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Posted 26 December 2017 - 12:16 AM

I'm ready to loosen headbolts and the head will be free from the block.

Question, is there enough width in the front part of cylinder head for cam sprocket to pass though with the chain installed around it, as I lift head off?
Alternately what.. you have to remove front-case to gain access to the timing chain tensioner / remove a timing chain guide to slack the chain enough to get cam sprocket out first??

#19 croquest87

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Posted 26 December 2017 - 07:12 AM

Cam sprocket will pass through the head although a little tight  make sure to get the sprocket and dizzy drive gear unbolted from cam first and separated  there is a sprocket holder underneath will hold the sprocket for you then take out all head bolts in sequence along w the two small bolts that hold head bolted to the timing cover on top

#20 TajMan

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Posted 26 December 2017 - 11:57 PM

I got the head off and I was puzzled for a bit at first inspecting head-gasket surfaces up close, then I saw the gap between the intake valve on cyl #4.
BENT INTAKE VALVE
Then I'm sure it was driven for a little while running on 3cyl before it was stored for so long.
https://imageshack.c...9528/fO6qp0.jpg
https://imageshack.c...4167/uiqfr5.jpg
How does this usually happen, valve float with the stock valve springs at high RPM and valve hits piston?

I've ordered the parts I need to at least fix the 1 valve + valve stem seals and headgasket set and new head bolts and jet valve elimination kit.

I'm going to get by for now even though I wish I could throw a bunch of new and custom parts on it immediately. Low boost on the stock turbo will have to do until then. Look at this t25 turbo placed right here! with exhaust outlet U-pipe from the factory Saab car... it will be great
https://imageshack.c...9152/eutg9I.jpg

I think I will see if I can remove and gut that pre-cat thing immediately after the turbo.
I already made a custom intake pipe with 1G DSM blow off valve to go before the factory intake pipe ahead of throttle body.

Question, if I install an innovative wideband O2 gauge after the turbo in place of the factory O2 sensor, can I use narrow-band simulation output from the innovative and connect it to the factory 1-wire going to ECU?
https://imageshack.c...1337/BXA2NK.jpg

interior!:
https://imageshack.c...1752/W1M2hm.jpg

https://imageshack.c...3738/Ocp841.jpg

Will be a sweet ride after I body work the front a little and paint half the car.

Edited by TajMan, 27 December 2017 - 12:02 AM.





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