Megasquirt - X1/9 - no go: Grassroots Motorsports forum: Classic Motorsports

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Aug. 18, 2008 9:59 a.m. m4ff3w Dork

I get spark and fuel out of my MS, but the car won't start.

I'm unsure if I have the spark input/output correct. The car has a VR sensor in the distributor with 4 "blades" and is firing a single coil. The injectors are 143cc.

Can anyone see anything glaring obvious (I'm oblivious)j with the below:

Engine Constants Required fuel - 15.0 Speed Density Injections per cycle - 4 Injector Staging - Alternating Four Stroke Cylinders - 4 Port injection Injectors - 4 Even Fire

Injector Characteristics Injector Open Time - 1.1ms Battery Voltage Correction .08v PWM Current Limit - 55 PWM Time Threshold 1.0 Imjector PWM period - 66 Bank2 Specific Bank 2 settings - No

Tach input settings Basic Trigger 60.00 Trigger Angle GM options - Off Ignition Input Capture - Falling Edge Spark output Going high Spark output - D14
Aug. 18, 2008 10:04 a.m. John Brown UltimaDork

Is the coil firing?
Aug. 18, 2008 10:08 a.m. m4ff3w Dork

Yes, coil fires and I do get fuel.
Aug. 18, 2008 10:26 a.m. sachilles New Reader

The old adage "Its either, Air, Fuel or Spark".

If this is a project that has been sitting a while before this moment, are you sure your gas is OK, along with your plugs? I know those are basic questions....just trying to cover the baseline.
Aug. 18, 2008 10:28 a.m. John Brown UltimaDork

I know that this wouldn't happen to you but...

When I worked as a tech we were installing a new engine that was recieved in long block form and the tech rushed and slapped it in only to find out that is seemed like zero air and fuel was entering the engine.

It seems that no one bothered to pull the tape from the intake manifold and it was not getting much air if any...

You didn't tape the intake did you? ;)
Aug. 18, 2008 10:40 a.m. m4ff3w Dork

Car was running last week. Car died on highway, seems the stock nearly 30 year old ECU died.

I could not locate one, had MS in the garage, and put it in.

I really think it is something with the ignition trigger or spark output not occurring at the right time. The car has good compression (160psi) cam timing is spot on, injectors are spraying, and I get spark from the coil.

I'm just not positive I have everything in MS correct. I think everyone running MS in an X1/9 is either using fuel only or have converted to EDIS or similar.
Aug. 18, 2008 1:09 p.m. Nashco Dork

Is it spitting and sputtering or are you getting nothing? Have you tried starting fluid to get a better idea if it's spark or fuel that's giving you fits? Have you used a noid light to make sure the injectors are firing as you'd expect? A little more info will go a long way to narrowing down the problem.

Bryce
Aug. 18, 2008 1:28 p.m. m4ff3w Dork

If I remove an injector I get good fuel spray and atomization. The car doesn't try to run on ether, but I do get BIG backfires with either or fuel after trying to start for awhile.
Aug. 18, 2008 1:47 p.m. sachilles New Reader

Coil is firing. what about downstream from that. Plugs look OK? Seems like fuel is OK from your description. Seems like you are either not getting adequate spark at the plug, or you are completely out of time. Make sure the plugs are OK......at this point you've probably tried turning the car over so much that the plugs are fouled anyway. If the plugs are getting spark, you are either out of time or air doesn't seem to be getting in.
Aug. 18, 2008 2:01 p.m. m4ff3w Dork

replaced the plugs yesterday, ones we pulled out were pretty wet. When pulling plug and cranking, I do get spark.

It is definately getting air, you can feel the vac on the line.

Seems to be waaaaaay out of time.
Aug. 18, 2008 2:23 p.m. Dr. Hess UberDork

Timing. With timing set at fixed, 10 BTDC, what's your timing light show?
Aug. 18, 2008 2:35 p.m. m4ff3w Dork

I'm not near the car now, I'll check.

Just to make sure I'm not being dumb and trying to do something I can't: The only input I have into MS for RPM is the VR sensor in the distributor. I am also trying to use MS for spark, outputting directly to the coil.

Does MS need more infomation (like a missing tooth wheel or something)
Aug. 18, 2008 2:47 p.m. Paul_VR6 New Reader

No it only needs one pulse per desired ignition event if using a distributor. If you're getting RPM reading (sounds like you are) I would bet on the ignition timing. You can vary your trigger angle or your distro location to see if you can get it close enough to start, and then dig out the timing light.
Aug. 18, 2008 2:51 p.m. m4ff3w Dork

Yes, I get RPM signal.

Thanks yall.
Aug. 18, 2008 3:15 p.m. Dr. Hess UberDork

How many cogs are in the dizzy? A 4AGE 20v has a whole bunch. A 22R has 4. Setting the 22R up with a single coil is easy. Setting the 20v up for waste spark is a PITA.
Aug. 18, 2008 3:41 p.m. m4ff3w Dork

4 "arms" on the dizzy.
Aug. 18, 2008 3:47 p.m. dan_efi New Reader

I'm suspicious of your "injector characteristics" settings. Which MS board version? What's your injectors' impedence?

Have you been trying different cranking pulsewidths?
Aug. 18, 2008 4:04 p.m. Jensenman UltimaDork

I'm having to go on my Swiss cheese memory of mine, but doesn't the dizzy run off of the oil pump shaft? Reason I ask, 1) the T belt could have jumped a tooth, 2) the dizzy drive gear roll pin could be sheared, 3) the oil pump shaft drive gear could be turning on the shaft (pin or key sheared). Any of those could explain your original problem and also why it's really hard to start now.

The dizzy has 4 'teeth' which turn with the shaft, they line up with 4 matching 'teeth' on the pickup coil. It makes one pulse when they all line up.
Aug. 18, 2008 4:37 p.m. m4ff3w Dork

They are low impedence. I've played with the pulsewide a bit.

The cam timing was still spot on with the old ignition module even after the initial breakdown, 12* IIRC.
Aug. 18, 2008 4:50 p.m. Jensenman UltimaDork

The cam timing? I'm confused. If you mean the ignition timing, then I'm not confused.
Aug. 18, 2008 4:55 p.m. m4ff3w Dork

That is what I meant. I'm tired and confused and used to a dizzy mounted on the cam itself.

The timing light flashed at the notch when it was supposed to.

Sorry for the confusion.
Aug. 18, 2008 7:08 p.m. RussellH New Reader

A couple of thoughts:

Can you pull the spark plugs, put a cork or something in there, pull the fuel pump fuse and crank while watching the spark? just before the cork pops out is about when you should see the spark, since they're set to batch fire watching any one would be good enough. If that checks out you can do a similar test for the injectors with the noid light or a homemade test light (do you have the test board for MS?).

Two, you said you're running the injectors directly from MS, I'm assuming you have the relay board that you're connecting the injectors to.
Aug. 18, 2008 7:28 p.m. m4ff3w Dork

No "relay board" but the injectors have switched 12v and ms just grounds them.

Good idea w/cork. Will try that once I get back to the car.
Aug. 18, 2008 10:13 p.m. Scott_H None

I know the FIAT twin cam time off of #4. This has looped many a tech (this one).

>Scott
Aug. 19, 2008 5:45 a.m. SVreX UltraDork

When we did it to my Yugo (which should have the same motor as yours), we had the same problem. I discovered the very obvious timing marks on top of the crank were in fact NOT the correct marks. They are 180* off.

The correct marks are on the underside of the motor. The notch aligns with a bracket (maybe the alternator bracket?).

Fired right up once we used TDC instead of BDC.