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Spark issue? Rough running, down low


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#41 TajMan

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Posted 15 January 2018 - 12:32 PM

weird do-it-yourself-er and recycler,
and this alt came from my personal old '93 Stealth R/T TT that means something also parts from that car are being divided between my other cars
and I have a machinist buddy later this week says he can alter a pulley/bushing for me no problem,
so I'll probably give it a shot.





#42 TajMan

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Posted 23 January 2018 - 01:07 PM

Sorry long time,
first off I got the VR-4/StealthTT alternator working... haven't run the engine under its own power to see if belt ever jumps off, but should be good I think spacing is right. NEVER DO THIS, buy the eBay 100A alternator! But do as I say not as I do, I was able to succeed in my stubbornness. PM if you want to know details, it's pretty straightforward possible. I found an off-the-shelf V-belt pulley and a slightly longer belt.

It's been a tough short while. My step-grandpa Herb passed away and funeral was on saturday. He was 95 I wasn't extremely close or anything but he had been a big gearhead and motorcycle guy in his life! Big family.. sad.

The Conquest... I have where it should run, gas tank back in tested its pumping fuel to the engine bay.. but I can't get it started!
At first it was almost-starting with some throttle and backfiring, I know it's close.

Compression, fuel, spark.. let me detail.

Compression - the check I did when I found dead cyl problem initially, cyl 1 2 and 3 were around 110psi on my gauge, #4 was zero. Now that head has been rebuilt and reinstalled, I'm reading about 90psi #1 and about 110psi for 2 3 and 4. Obviously very frustrated at cheap machine shop, I believe they didn't keep valves matched up with their proper cylinder and just did new valve grinds maybe not lapped valves enough... hope it improves a little with running, but it should have compression to start!

Fuel - like I said, getting fuel to engine bay. I'm suspect though because you power the fuel pump test connector.. and gas comes out of the line by the throttle body at a slow flow like a carbuerator's fuel pump, not a higher pressure fuel injection pump. ??? Is this normal, possible bad pump? I've tried holding throttle open and spraying a little starter fluid in, it hasn't caused the engine to fire as if there was a fuel issue and this leaves me puzzled.

Spark - I'm definitely getting strong spark. I pulled a plug and checked, spark was bright and then it shocked me so coil is working. I'm only suspect I have something set wrong. Aren't you supposed to set the engine at TDC, then install the distributor so the rotor is pointing about 15 degrees ahead of cyl #1 spark plug wire?

Once I can get it to idle I'll set the ignition timing with timing light.

I'm 99% sure I have the mechanical engine timing correct... doesn't the fact I have similar compression numbers (to stock or what I was reading before) confirm that should be ok?

#43 croquest87

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Posted 23 January 2018 - 03:24 PM

She will run  not sure how good but will run   establish and check your fuel pressure w a gage for sure.      
  no proper fuel =leaning out and boom something gets burned up and glowing hot.   detonation soon after

#44 TajMan

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Posted 25 January 2018 - 03:49 PM

If you install a Walbro GSL392 (350hp capable? 550-600hp capable?) fuel pump, does the stock fuel pressure regulator keep it in check.. or more aftermarket required at that point?

Edited by TajMan, 27 January 2018 - 03:47 PM.


#45 TajMan

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Posted 27 January 2018 - 03:42 PM

Finally got it started! Not sure why so hard, but after swapping distributor 180 degrees a bunch of times, and adjusting the dist one tooth forward-back.. finally got it, got timing set 10 degrees btdc.

It idles ok. However, when you try to rev, it doesn't respond as it should it didn't feel smooth.
I couldn't understand then it dawned on me.. I think it's the fuel pump! Not pumping near what it should.

Back to question please, will the stock FPR handle the upgraded Walbro, or does it require an aftermarket adjustable fuel pressure reg to go along with and keep it at proper pressure?

#46 croquest87

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Posted 27 January 2018 - 04:43 PM

Should be fine  what is your pressure on the gage?

#47 pcristquester

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Posted 27 January 2018 - 08:53 PM

The stock fpr should be fine with your walbro. I ran mine on a Bosch 044 pump with no issues. I would suggest and adjustable fpr, though. Spa Turbos and Trilogy Turbos have adjustable units for about $140 that mount up to the stock top hat like OEM
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#48 TajMan

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Posted 28 January 2018 - 12:29 AM

View Postcroquest87, on 27 January 2018 - 04:43 PM, said:

Should be fine  what is your pressure on the gage?

I haven't tested with a gauge... but in a case like mine when flow is SO bad I think it's more obvious.. and after able to idle and confirming that's about as far as it can do 'smoothly'


Also, there were aftermarket fuel rails for the stock 2-injector setup on eBay with an open threaded port to go to an AFPR... I swear they were listed at like $70, but I can't find anything on there currently!

It's just too bad the next step to flow more requires something like a MAF-T + an SAFC-II... too much on electronics for something temporary, I had planned on a MPFI conversion soon as I'm able (!! the intake manifold I was waiting for just came in the mail!).

Maybe I'll take apart the stock FPR on the stock rail... I bet it could be drilled/tapped for a pipe-thread fitting... that I could adapt to my own AFPR I last had on a DSM.

Edited by TajMan, 28 January 2018 - 06:01 PM.


#49 Edde

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Posted 28 January 2018 - 12:00 PM

I'd get it running right as stock as possible first. A good stock fpr is fine. An old pump obviously not.  I like to put an external hose to a bucket on the TB return port and run the pump on the 12v connector just to see how fast it can pump, and if the stream has air in it.

Glad you got the cam timing right.  It sounded like you would be off a tooth as it typically makes the pin slightly before 12, not dead on.
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#50 TajMan

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Posted 30 January 2018 - 01:54 PM

Trying to do some paint stuff now..

Edited by TajMan, 15 February 2018 - 11:03 AM.


#51 TajMan

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Posted 13 February 2018 - 11:48 PM

I finally got it on the ground and testing under its own power today, runs pretty crappy ugh so frustrating. Seems like and ECU/tuning thing, I really don't know. Unresponsive, sometimes even backfiring a little. When it's in park and you rev it, sometimes you can get the rpm's to rise and boost to build close to as it should, but sometimes it's stumbling having hiccups. Obviously a fuel/tuning related thing. I can check the timing again but I thought I had that on now.

The Walbro pump is in, the fuel screen located in the hose between the tank-pickup and the pump.. is not installed in the hose at all this time, so I KNOW flow restriction is not a problem now from tank all the way to fuel injectors I suppose I haven't watched them flow, but I think they're fine. New injector clips installed and all. I just feel like it's ECU related somehow since I just can't figure and it's just so weird but so close. I just realized I haven't tried testing the difference between unplugging the MAF plug, so I could try that..

I did by the way have the upper IC pipe modified with a 1G DSM blow off valve, but it wasn't responding right and it was leaking- I tried multiple intake vacuum sources with no luck. I ended up welding a temporary steel tube up so I could run it in stock configuration again, (so I need a new OEM rubber upper IC hose (the one that goes from radiator area to the steel pipe that goes over valve cover to the throttle body.)

#52 TajMan

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Posted 15 February 2018 - 11:02 AM

And just like that I get a click but no crank, starter issue. It's a loud click, like in engine bay starter gear engaging but not turning the flex plate starter teeth. Removed it, tested at the parts store.. it spins like it should, but that's of course with no load..
So I guess I'm getting a replacement now so I can move the car again and continue diagnosing. Motor spins freely, hope the new starter motor fixes it now.. I don't know if it's common for an old starter put back into use to work fine a few times and then die.

Is there a starter relay in the dash?

Edited by TajMan, 15 February 2018 - 02:37 PM.


#53 TajMan

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Posted 25 February 2018 - 06:18 PM

New Starter fixed it.
Interesting, AC Delco starter was't a gear-reduction starter as the stock was, and when I looked up that AC Delco part number I found one online same part no but different style than mine- it was a gear-reduction unit. Anyway, new regular style one starts the engine again, nice.
Still runs like crap, like a fuel/tuning thing. I just bought online a fuel pressure gauge I can install on the feed line. I need to remove injectors now and try to check them out/clean them myself.

I got an aftermarket front-mount IC to install. 2.5" piping, I'm going to see how I can manage routing. I almost want to use a different performance battery that is skinny, but still has enough CCA..
I guess I'll do custom IC routing twice, the first time for the stock turbo and stock TBI. ? I'd rather not do the IC piping until I build the custom mpfi setup later, but that means survive for now on the stock setup I know my IC has pinhole leaks i've tried to patch.. just need to get it so it runs ok at least

Edited by TajMan, 25 February 2018 - 06:25 PM.





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