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Discussion Starter #1
I just recently swapped a freshly rebuilt 6m into my mx73 Cressida. She was running pretty decent for about a 2 1/2 weeks when she developed a SICK bucking problem on acceleration. This then lead to a serious (and i mean very serious) hesitation problem. It was so bad in fact, the only way to measure the amount of pedal i could push down before the engine would stumble to near shut-off would be with a micrometer, literally. I would have to deal with this at 5am every morning for about a week until it somehow got its bearing and started to drive fine for the remainder of my drive (usually in the cold temps of the morning, but sometimes even after school).
I assumed it would be the fuel pump, filter, ignition timing, or vacuum/air leak.

The car is dead at my girfriends house AGAIN :32:

Basically i have very little tools at this point in time, and NO money.

I only have a socket set, a razor blade, and a borrowed fuel pressure set.
I couldnt fit the socket under the manifold to unhook the fuel line at the cold start injector, so i cut the fuel line before the filter and T'ed in the pressure gauge with a fitting. i get about 38psi before the filter when i jump the fuel pump circuit, and when i crank the engine.

I then cracked open the fuel rail near the pressure regulator and jumped the terminal to see if i got fuel past the filter, and i do. But the gauge reads 20psi before the filter with the rail cracked, so i assume the filter is consuming AT LEAST 18psi from the total pressure. Is this normal?
Could that drop in pressure cause my no start problem?

I just landed a new job that starts on Monday and have no way to get there now :/
I need this job more than anything and would appreciate any help from you guys.
I can try hard to borrow tools and such, but i have virtually no cash or credit to spend.

thanks,
Ryan
 

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First thing I'd check is all the intake lines for vacuum leaks.
 

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that sucks man, trying to fix a car without $$$$ , just recheck the basic stuff, timing, spark.

good luck
 

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Discussion Starter #5
Well there's a twist to the story. When I went to set the timing after the engine was swapped in, the only way I could get the engine to run was with the distributor advanced a full tooth. I double and triple checked cam timing and they're both dead on balls accurate!
That one threw me for a loop. I cant even set it with a timing light (nor can i even see the crank notch with the timing light), there's only that one sweet spot where the car will run, but it sure ran like a champ for that short time.

I replaced all of the vacuum lines when I was prepping the engine for instillation, and I do get spark at the end of all 6 spark plug wires. Spark plugs are brand new.
I'm probly going to take the intake manifold off and scope everything out.

I was curious as to how you get water in your gas? It has been getting cold and with all the dew in the mornings, it raises suspicion. Could I displace it with a can of Sea Foam possibly?

Could a miss adjusted TPS cause a no start?
 

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You can remove the fuel line before the filter and pump it all out. If it is that


The car will run with the tps out of adjustment. It will even run with out it hooked up.

One thing to check before you drain the tank is to make sure the ground on the intake is good.
 

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Does it hesitate when the engine is warm or does it hesitate as soon as you started cold and drive off! If it only hesitates when warm, you might be looking at an arching pick up coil in the dizzy! If you can find a used dizzy at a junk yard it'll run ya about $40! If not, check your fuel filter! If your car has an external fuel pump, there is also a primary fuel line filter just before the fuel pump! (Again, only if its an external fuel pump!)

Good luck to ya!
 

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My car has a hesitatation when I first start it up and take off. After that hiccup, she's fine. Vaccuum or other? I dunno, it's been like that ever since I owned the car. :confused:
 

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Discussion Starter #9
You can remove the fuel line before the filter and pump it all out. If it is that


The car will run with the tps out of adjustment. It will even run with out it hooked up.

One thing to check before you drain the tank is to make sure the ground on the intake is good.
I cleaned all of my grounds and the intake ground is good for sure, i've had problems with that one being unbolted before. haha

Does it hesitate when the engine is warm or does it hesitate as soon as you started cold and drive off! If it only hesitates when warm, you might be looking at an arching pick up coil in the dizzy! If you can find a used dizzy at a junk yard it'll run ya about $40! If not, check your fuel filter! If your car has an external fuel pump, there is also a primary fuel line filter just before the fuel pump! (Again, only if its an external fuel pump!)

Good luck to ya!
Well at first i thought it would be just in the cold temps, but then it started happening all of the time, warm and cold. I have a spare dizzy that ill try out. I never even thought that the spark could ground out via the pick up coil, but it does make sense if its the easiest path to ground!
 

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Never seen a pick-up coil arch. I have seen Ign Coils arch across to ground.

It would not make spark at the coil if the pick-up sensor went to gound.
 

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Never seen a pick-up coil arch. I have seen Ign Coils arch across to ground.

It would not make spark at the coil if the pick-up sensor went to gound.
Yeah, you know what! I was thinking about it a second time and when I had problems with my dizzy, I thought it was my ignitor and Ign coil! Actually my car would'nt start cause the pick up coil in the dizzy was bad. There for not passing spark to the coil and to the plugs! So if his car does run, then it cant be the dizzy, cause it wouldnt stay on in the first place. Now it sounds to me like eather a fuel problem or a timing problem, since he said that he had to retard the dizzy to get it runnin! Makes sense?

The reason I thought the pickup coil was arching is cause I also own a Nissan Xterra and when the engine was warm, it would hesitate and could not go over 25 mph! Then I found out it was the pick up coil! When I changed it, I found out that the magnetos broke and it was arching bad! You could actually see the burn marks it left on the dizzy stem!
 

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Discussion Starter #12
Well I do get spark to the end of each wire. So the igniter works, and the pick up coils work (for both spark and injector timing). But the car wont start, to do any further testing. I can hear faint pops in the exhaust like it almost has a partial burn at random when I crank though.
 

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I know this may sound dumb, but have you looked at your plugs lately! And if you have, did you gap them correctly? Dont worry, ain't judging! lol
 

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Discussion Starter #15
Haha, nahh I gotcha.
The plugs have maybe 40-50 miles on them. I inspected them and they look brand new!

With the crank at 0 degrees TDC, the cam timing marks line up PERFECTLY to the timing cover notches. The belt is brand new, as is the tensioner.
 

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My car has a hesitatation when I first start it up and take off. After that hiccup, she's fine. Vaccuum or other? I dunno, it's been like that ever since I owned the car. :confused:
I thought that was just my '82.. weird. Mine does that exact same thing.
 

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run a 10 btdc on the crank with cam gears lined up correctly!!!
run a higher octane though
the 6m's really like 10 degrees

so you have spark
and you have air
now are you getting fuel?
check to see if injectors are pulsating
 

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Discussion Starter #19
So I should align the Cams with the crank at 10 BTDC, or at 0 TDC and time it to 10 BTDC via moving the distributor?
But yeah i have spark, air, and fuel. Although I'm not sure if i have sufficient fuel pressure.

How can i check for injector pulse?
I've used a socket extension as a stethoscope before, but that was when the engine would idle. And I don't think I'd be able to hear them over the starter.

I don't have a noid light either, but i do have a DMM!
 

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this is what I would do!

I would set the CRANK to 10* then align cams
next i would leave the dizzy where it is at! but usually i set mine in the middle and advance it untill it starts to ping.
this will require you to run a higher octane 87 should do it

or get a timing light
 
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