A Rebuild Story - A Forged MP3 Motor

[TurfBurn]

but I'm saying, when are YOU gonna get some numbers published? I'm dying to see the fruits of your labor

Hopefully by the second week of May the first numbers will go up.. I probably won't get my ignition until June or July... so we'll see what happens before then... but then I'll have individual Bosch Coils driven off the Microtech X4 module hehehhehehehee.


Just ran a compression test... keep in mind this motor has about a whopping 15-20 minutes on it... so the rings are not seated all the way yet... I got compression readings on this 8.9:1 motor of 126-129 across all 4 cylinders... so within 3 psi of each other is good news.. also means my valves should all be good so one less worry! Now to figure out timing and see if it is sitting right.

later.

Steve

 

[changedman]

very nice. thats a low comp for 8.9:1...

 

[TurfBurn]

very nice. thats a low comp for 8.9:1...

Yeah... like I said though the motor has like 20 minutes on it... the rings aren't even close to being seated at all yet...

Still is running like complete crap... The AFR's are pulled in relatively close to where they belong (about 13-15 below 0 inches) and it just dogs and misfires most of the time.... I get really bad breakup at 3,000 rpm's... and then it will hold for a while and I can get occasional misses and the like above that... so I'm a little stumped right now because it isn't being cooperative.. I can't do anymore tonight because the car is too loud to be on the roads in this neighborhood at this time. So she'll have to wait until Friday night or Saturday I guess...

Little frustrated that it is still being so uncooperative... I may switch out the big injectors and drop in the stockers just to see if that cleans anything up or not... I highly doubt it as I never had this problem before... I am wondering if it is the plugs... I've got stock mazdaspeed platinum plugs in there gapped at 30 thousandths.. I'm probably going to switch them out to BKR6E's at 30 thou and see if that holds... dunno.. stumped! But the oil is clear and staying clear now with the last 10 minutes of driving on it... so that's good... and the spec stage 3 rocks

 

[TurfBurn]

Oh and ignition timing is dead on....

 

[changedman]

platinum? blech. just my .02

i was running on the NGKs as well, i was happy with mine after we got the engine in, started right up after prep, was ready to drive about 1hr after the first start!

 

[TurfBurn]

platinum? blech. just my .02

i was running on the NGKs as well, i was happy with mine after we got the engine in, started right up after prep, was ready to drive about 1hr after the first start!

Yeah I hate platinums as well... but they were stock Mazdaspeed plugs.. and extended reach... which is great for starting up a car... but I'm thinking I'm getting ***** by them.. I went over some of the symptoms and the like with Little Beavis and we both are leaning heavily toward it being ignition related... so I'm going to switch plugs... and go from there... I have an oscilliscope so I'll tap the ignition signals and verify how things are running and that solid signals are going out... I also have inline signal lights for checking the spark in the engine bay so I'll add those in... so overall I'll beat this problem to death until it goes away... but as of right now car runs like ass... but hey.. it runs so I'm happy about that .

Later,

Steve

 

[changedman]

yeah, at least yours runs right now....

 

[TurfBurn]

Ever figure out why that valve went on you?

But look at it this way.. until this week I was without a car since June 21st of last year... so But yeah I know how you feel! I'm just hoping it holds up for at least a year for me.

 

[changedman]

haha yeah....

we are pretty sure something must have gotten stuck in the head or something and bent the valve on its way out... because all the spark plugs looked fine, it held 165lbs comp on each cyl and everything else was ok....
I've been without boost since october, so does that count as going without a car? it should

but hopefully my car will be back in Michigan in a couple weeks

 

[BlkZoomZoom]

You are aware that cam timing events being off will cause low compression on all four cylinders also?

 

[TurfBurn]

You are aware that cam timing events being off will cause low compression on all four cylinders also?

No, I hadn't heard that... but I've checked the cams several times... I plan on checking them again on Friday before I try running as it is one of my concerns at this point even though I have checked them repeatedly. I have both timing marks lined up perfectly at centerlinewhich results in the intake and exhaust lobes for cylinder 1 pointing roughly 170 degrees apart (exhaust lobes pointed toward front of car, and intake lobes pointed back at the firewall) which all matches out to what it should be as far as everything I know and have double checked in the shop manuals. If you have any suggestions or thoughts on that please do let me know! Otherwise ignition is the only thing we really suspect..... keep in mind the car runs smooth from an engine standpoint in the higher rev's but just has ignition misses etc where it backfires and stutters but is otherwise smooth... and slowing down with the clutch engaged it runs super smooth as well.... but yes, cams and ignition are where I believe the problem lies, but I can't seem to find it just yet.

 

[VizaX]

Use an Ohm Meter and check your Spark Plug wires... I doubt it would be that, but my wires went out and I had Cyl #1 and #3 Misfires... could be it.

 

[changedman]

your WIRES went out?! hmm, sounds fishy.... who told you that? a dealer?

 

[TurfBurn]

It's worth a try... wires do degrade with time and the resistance goes up on them... so I'll give it a go along with other things.. if things go crappy tonight/tomorrow I'll post videos to get additional opinions...

Later!

Steve

 

[changedman]

well its weird because wires 1 and 3 are on different coil packs, just odd they would both cause a misfire at the same time...

 

[TurfBurn]

well its weird because wires 1 and 3 are on different coil packs, just odd they would both cause a misfire at the same time...

Yeah THAT would be odd.. but one of them going or them both being intermittent would be reasonable...

So anyway.. I'll get to work on my car in a bit over an hour... but here is my "symptoms" list right now..

Idle SOUNDS lumpy, but overall is smooth (as far as the motor itself.. no excessive shaking etc). Exhaust note is very aggressive and separated... like a drum beat... has been likened to an idling Harley... idling at 880 rpm's and 10-14 degrees timing.

Exhaust sounds breath and the car hesitates and stumbles while trying to accelerate or rev until above 2200 rpm's... once above 2200 rpm's feels pretty smooth but will occasionally misfire.

At approximately 3,000 rpm's complete ignition breakup occurs with constant misfire's and gasoline vapor lighting at the tailpipe (backfire).

Can not accelerate through the breakup... AFR's remain reasonable constant but will show lean dips following misfires etc.

JandS does NOT see detonation but will show occasional noise.

On deceleration, no misfire or roughness at all and good clean exhaust note all the way down... but injection is cut during deceleration currently, no fuel is dumped.

So that's the story currently... In order of suspects... I believe it is sparkplugs/ignition, injectors (but have been cleaned and reconditioned for this rebuild), or lastly camshaft timing (been checked repeatedly and seems to match everyone elses and is timed properly in the car itself).

So that's it... If I figure it out I'll let you know but I'm certainly interested in any and all suggestions... remember there is NO stock ECU, just the Microtech.. so no cam sensor or the like to worry about... and the Microtech shows all good readings on all sensor banks and reports no errors.

Thanks!

Steve

 

[jurgs01]

I know you have probably already checked, but are all of your vacuum lines on correctly and tight. And you also said you had something wrong with your exhaust (cat blew out?). Is your first o2 sensor reading correctly?

I went through ignition troubleshooting lately. It's easy to check all of the resistances. I doubt the platinum plugs are your problem on idle.

 

[TurfBurn]

Well... she runs! Fricken plugs... I switched them out and changed the Microtech over from Batch to Sequential fire on the injectors and just like that it runs perfectly. It's great, very smooth, very responsive everything is excellent...

BUT i developed a new problem after a little while of driving... my battery voltages are basically off the chart high... over 15.8V all of a sudden... I have no idea what is causing that... seems like the alternator is confused and is going crazy on trying to charge... Never seen a problem like that before so I'm a bit confused and I'll have to work out what is going on with that now.. so another problem to hurdle.. but I put on about 10 miles of easy cruising and accelerating to work those rings in... but everything is trimmed in great!

Later,

Steve

 

[BlkZoomZoom]

Iat sensor showing bad readings?

 

[BlkZoomZoom]

Wait a second you don't have the stock pcm. How are you trying to regulate the charging system? Does the Microtech take it over? The stock pcm uses several different inputs to determine how much charging the altenator should do. Without it I imagine it would either full field the alt. or put out zero. Maybe you will have to re-wire the set-up to incorporate an old style voltage regulator.