have spark and fuel, still won't start??

[noname7198]

We've got a track only s13 coupe with a redtop sr installed. No chassis harness, just an engine harness.

Build thread here:
http://www.zilvia.net/f/showthread.p...ht=coupe+track

We have spark and fuel. When we push the start button the motor turns, but sounds like it doesn't have enough power (like a dying battery). The battery is fully charged. We also tried a new battery, but still it barely turns. The battery is in the trunk, running 4 gauge wire straight to the starter. The starter has been tested and is working. We have a seperate switch wired to power the ecu and everything else that gets 12v power. We get ecu codes 12 (maf) 13 (coolant temp sensor) and 34 (knock sensor) but none of those should prevent the car from starting.

We are out of idea's. Can anyone think of anything else that could be preventing the car from starting?

[PhopsonNY]

How did you do your timing?

[noname7198]

its a freshly rebuilt motor. We aligned the marks on the cam gears and put on a new chain following the fsm. If the timing was off would that prevent it from starting? I'll try to get a timing light to check the timing tomorrow.

[RedtopTech]

Check for b+ voltage at the starter. If the voltage at the starter is more than a few tenths less than what was read at the battery then you have excessive resistance in the power wire. Next measure the amperage draw during cranking. An excessive amperage draw will be the result of a problem with the starter itself or a mechanical issue with the engine. The latter issue can be ruled out by ensuring that the engine can be rotated by hand or by attempting to pop start. Another thing to be noted is a proper battery ground. Proper circuit design will utilize wire of the shortest length necessary and of a gauge that is thicker than the expected circuit amperage draw.

[RedtopTech]

improper valve timing will not cause the symtom that you described. In fact it would cause the engine to spin faster due to the increased overlap or compression loss from the out of sync valve events.
Also you could remove the spark plugs prior to cranking to rule out this unlikely scenario.

[RedtopTech]

If RhopsonNY was reffering to improper IGNITION timing, loud, popping misfires would acompany the reduced cranking speed. This is a common scenario with spark triggering that is 180 degrees out. This could be ruled out by disabling the fuel system (pull the pump fuse.)

[clark]

i've experienced something very similar to the symptom you described with my s13 sr20, but i never bothered checking for codes.

it happened after i installed some rocker arm stoppers. the torque wrench i used was a piece of shit and hate myself for being dumb enough for believing it...

anyway, i ended up tightening the cam cap bolts too tight, and the cam cap/towers/whatever you calll them were way too tight and creating alot of drag on the camshafts. (i only tried to crank the engine twice and knew immediately i fucked something up so i stopped).

loosened all of them (in the proper sequence) and re-tightened them with a regular ratchet until they were tight enough. slapped my valve cover back on and reconnected everything and it started right up.

so my question to you. how did you torque down the cam towers?

[PhopsonNY]

There is no single symptom that accompanies all conditions of bad timing.

If you have spark and fuel, the last critical element is timing. It is critically important to get the timing right and despite following the FSM and FRSPORT.COM instructions, you can still get it wrong.

I would just check that you have your cams aligned properly again and check the CAS also. In addition, make sure your chain guide is properly aligned.

This comes from personal experience that paralleled yours. I had no popping or backfiring... just slowly turning over but no start. Redid my timing very carefully and got it going.

Good luck.

[RedtopTech]

changed my response

[RedtopTech]

Friction, mass, and dynamic compression are the only variable that can change the amount of torque that is required to spin an engine to a certain speed. The only of one of these variables which camshaft timing can affect is dynamic compression. Now although camshaft timing can be manipulated (variable valve timing, adjustable cam gears, and installed orientation in the case of push rod engines) in order to optimize the amount of air introduced into the cylinders (which raises the dynamic compression) at given rpm by utilizing pressure waves and scavenging, at such a low rpm as when cranking, these effects would be miniscule at best.
Now there is a scenario where a reduced cranking speed could be "percieved" as the result of improper valve timing. If the ignition system of an engine is timed/triggered via the camshaft, then an improper installed orientation of the camshaft would result in improper ignition timing relative to the position of the crankshaft. The result of this situation could cause an increase in the amount of torque required to spin the engine to a given speed since the starter motor now has to overcome the force of combustion working against it (if the cam orientaion results in the ignition occuring during the up travel of the piston.) Also if the spark were triggered during the up travel of the piston, then a valve would be open at that time which would cause the loud popping noise.
The improper valve timing would cause improper ignition timing however the ignition is still the cause of the "slow cranking and popping."

[RedtopTech]

I wouldnt be so quick to over look the codes stored in the computer. The computer will set these codes when it recieves a sensor input that is out of the expected range of values.
The MAFS should output less than 1 volt with the key on and engine not running (KOEO.) At idle you would see a value b/w 1.3-1.7 volts. At WOT this sensor should output more than 4 volts but never more than 5.
The coolant sensor outputs a voltage based on the resistance of the sensor. When cold the sensor's resistance is very high. As the temperature increases, the resistance decreases. As the resistance drops, there will be more voltage left in the circuit according to Ohm's law.
Now understand that an engine requires relatively more fuel to initially start than it does to hold a low idle. Also a cold engine requires more fuel to start than a warm engine. Also the ambient temperature will greatly increases the fuel needs of an engine to start.
So since you have codes stored for the two sensors that contribute the most for the computer to calculate the ever changing fuel needs of the engine.
Im sure it's not to cold outside in MA right now so the engine doesnt require a very large amount of fuel to start. If the MAFS is telling the computer that there is 4.v+ worth of air pressent while cranking, the injectors would deliver as much fuel as it would at >4000 rpm at WOT!
Now consider that the coolant sensor may be out of range high, so the computer also thinks it's really cold outside and delivers even more.
These values are exagerated over what it would actually take to overfuel the engine but the point is that even the best ignition system's would'nt be able to ignite a mixture if it's just to rich. This unburned fuel would flood the engine and drastically reduce the cranking speed if not hydrolock it.
leaking injectors/ o-rings could cause the same symptom but doesnt explain the codes. Just a theory!

[turboh224g]

I am the other guy working on this car. It is in my garage near philadelphia. I do not believe the low cranking speed has anything to do with timing. The reason I say this is because we are running an engine harness only and have a direct wired fuel pump and starter. Before trying to starting the engine I will leave the power off to the ecu and the fuel pump and just turn the engine over to get oil through the system. After a couple of rotations I will stop turn the fuel pump and ecu on and try starting the engine. During these actions there is no change in cranking speed at all. Before cranking we have over 14 volts at the starter, but there is a significant drop while cranking, how much I do not know. I am wondering if during cranking the starter is simply not gettting enough power? What could be causing this drop? Thanks,
JKP

[PhopsonNY]

I am not saying that timing is definitely the issue, but if you can get the engine to turn over consistently, albeit slowly, it would suggest there is enough power to start.

If there is spark and fuel at all cylinders... timing seems and obvious next thing to look at. Of course there may be other things causing it, but it would be smart to eliminate timing from the list before ripping your harness apart looking for a short.

http://forums.nicoclub.com/zerothread?id=222395&page=5

There have been a few posts here and on NICO where people had to carry out the timing procedure multiple times before they got it right.

If the car is on wheels... can it be push started?

Good luck

[superaudi]

the slow cranking is always related to battery problem. the flow of battery current is the main thing. both possitive and negative have to properly installed. and most likely if you put the battery at the trunk the ground is the problem. try to add ground wire from the engine to the body, or you can try to run from the engine straight to the battery, the bigger wire the better. it always work for me.

[clark]

noone really wants to take my suggestion into consideration lol???

i'm not lying..this really happened.

judging by your description, there seems to be something somewhere creating excessive drag.

maybe have the starter tested..?

also you said you ahve a switch to power the ECU. are you powering the ecu using a relay of some sort?

also, see how difficult it is to turn the crankshaft with a breaker bar that's how i ultimately realized where my problem was. i was BARELY able to turn it. you should be able to turn it with minimal effort if using a breaker bar with a long shank. i think it's a 22M or 24MM on the crank shaft nut but i could be wrong.

[noname7198]

The motor rotates easily by hand. I cleared the ecu codes, now the only one we get is 34.
I added more grounds, we have 1 4 gauge in the trunk and 1 8 gauge in the trunk (directly from the battery). Also added 2 8 gauge grounds from the intake manifold. 1 to the frame and 1 to the fender well. And added an 8 gauge ground from the transmission to the frame. I took a dremel to the bolts and chassis where the grounds are to make sure they are clean shiney bare metal.
Now the car sounds a little better, but still kinda weak. I did get 1 small backfire trying to start it.

Would running a ground from the motor directly to the battery help? Is 4 gauge wire big enough for the positive side from the trunk to the starter?

[dori_sil8t]

first check that u have the ecu ground connected.. its under the fuse panel pas side..
second check that u have the wiring correct on the pas side where the battery used to be. the ecu back up power wire is on that plug plus other that u need to have connected.

[noname7198]

we tried push starting it, but when we pop the clutch the rear wheels lock up. We tried to pull it while it is in gear and it just drags the rear wheels.

[RedtopTech]

So the car rolls freely with the clutch in? However unlikely, pull the plugs out to rule out hydrolock since its quick. Next follow CLARK's advise and remove the cams (in sequence using at least 4 steps) and then attempt to rotate the crank (hold the chain up and taught. This would eliminate the head as the problem.

[noname7198]

The ecu ground is connected and so is the back up power, but not in the stock location. We have no chassis harness at all, no fuses and no relays. The car cranks, but still sounds like it's not getting enough power. It rolls freely in neutral and with the clutch in, but in gear the the rear wheels lock. It also turns easily with a ratchet on the crank pulley.

[RedtopTech]

have you measured the amperage draw of the starter?
If the engine turns by hand and the car rolls freely with the clutch in, the wheels should only lock if you the trans was stuck in reverse.
Not using any kind of circuit protection, esp. on a fabricated harness, is not a good idea.

[clark]

Originally Posted by noname7198

It rolls freely in neutral and with the clutch in, but in gear the the rear wheels lock. It also turns easily with a ratchet on the crank pulley.

with your rear wheels locking like that when you try to roll start it makes me think you may have a clutch related problem...? but then again, you say it DOES rotate rather easy by spinning the crank pulley. i've seen cluethces being out of spec and just causing all types of mayhem with the pressure plate/flywheel creating alot of drag? i may just be on crack. fix this issue it's killing me now!

i think redtoptech is on to something though, your electrical setup seems a little janky

[noname7198]

I went to a local shop to ask about the problems. They think the rear wheels locking is probably just because of the car being so light and having a 2 way lsd.

We tried jump starting it and it sounded fine (like a normal car trying to start) but still didn't start. We took out the injectors and made sure they were all firing again (they are) and checked for spark on all four coilpacks again (there is spark). Now trying to start it on it's own it sounds like it should, but still isn't starting.

[xsparc]

Just some thoughts but whats you spark gap? when your trying to start does the system drop below 10v? Are the injectors the right size? have you tried to hook a timing light up to number 1 and make sure its fireing at 15BTDC?

[noname7198]

Plugs are gapped to .030. Havn't checked the starter when cranking. They are stock 370cc redtop injectors. We don't have a timing light, but we're pretty sure the timing is set correctly.

[xsparc]

pretty sure and sure are way differnt. I spent like 2 hours trying to figure out why wasnt starting, did the timing light thing and saw i was at like 30atdc

[noname7198]

I doubt this is the problem, but I'll ask anyway. The ecu has "180sx" hand written on it. There is a big number 62 on it and below that is A11-000 RG3. That is a red top ecu right?

[noname7198]

This is a freshly rebuilt motor. Using the FSM we lined up the silver and gold links on the chain with the dimples on the crank and cams. Could timing still be off?

[xsparc]

Line up the CAS too? you didnt by any chance swap the intake and exhaust cams did you???

[turboh224g]

the key ways on the intake and exhaust cams are different lengths so the cam gears will not fit properly if reversed. We also set the cas according to the fsm. JKP