Rough 7

Hi all, I just got my ’88 GTU (n/a) back up and semi-operational after many years of sitting. I used to autox and attend track days, but had to be responsible for a brief moment and I'm finally back to bad habits again!

Goal is to have a fully track-day capable car that I can drive around town as well. Currently it's up and driving, just not happy yet.

Some quarks I was curious for some input on:
1) The Tach no longer works (new problem) – preliminary research says the trailing coils – question is are either Rockauto brands adequate for the old Denso coils assuming this is the issue? What voltage should I be getting on the coils with a voltage meter before I order anything?
2) Trouble starting the car – spark plugs haven’t been replaced in 8 years of sitting, nor the spark plug wires (new battery though). Any opinion on best bang for your buck on the plugs and wires? It looks like I can spend from $2.50-$30 per plug and anywhere from $5-75 on the wires depending on the brand, etc. Again, looking for a fun track day car that can be driven around town, don’t need hot plugs (I’ve figured out this much!). Not sure if the cheapest option is the best idea either though.
3) Windshield wipers stopped working – kinda took me by surprise while driving around, but don’t work at all. Did some basic searches and don’t think it’s the switch, so go ahead and order a new motor? (Fuses look good and will double check the connection at the motor when it stops raining here). Any preliminary tests I can do to see if the wiper motor works at all?

Any other basic tips are appreciated. Thanks again!

DC5Daniel

iTrader: (10)

For your tach issue, the coils rarely go bad. However, I did have an intermittent tach issue which was remedied when I switched coils (IGN1A, not stock). Used coils are very cheap, if you do some due diligence and verify the integrity of the connection from coil to the cluster, I'd try a good used coil.

Plugs, go on Mazdatrix, they do a great job of identifying stock replacement as well as alternative. Plug wires just do a set of NGK and be happy. Relatively cheap and reliable.

Wipers, I seriously doubt it's the motor....95% of the time, it's the switch. What makes you believe the switch is good?

Rough 7

Daniel, appreciate the notes.

NKG sounds good to me and I've looked into used coils. $15-25 or so each sounds way better than $100+ for the cheap RockAuto ones.

I'm thinking it's not the switch mainly because none of the settings work on the switch... it's not like the slow setting works, but int and fast doesn't (or some other variation)... which seemed to be a common symptom of some of the threads where the switch was bad. Could certainly be wrong though, that's all I'm going on. It's been raining the past four days, so haven't been able to check any connections to the motor itself yet either.

I'm kinda hoping that the wiper and coil issues are both just faulty connections, but just trying to get my ducks in a row if I'm looking at replacement parts.

Thanks again for the tips.

satch

iTrader: (1)

Did you check the wiper fuse? If the fuse is good then place a ground on the Blue/White wire at the motor plug w/key to on and it should cause the wipers to turn on.

misterstyx69

iTrader: (142)

Bur7EQ and BUR9EQ plugs are the best bet (NGK brand) for what you plan to do.

Rough 7

Satch, appreciate the tip. Will do.

Styx, that's exactly what I picked up, so this bodes well.

Just put in a bid on a used set of trailing coils for about $30 plus shipping on eBay... high seller rating and huge savings if it works, seemed like it's worth a shot.

Thanks gents!

DC5Daniel

iTrader: (10)

Happy ending to this, or does the never ending rotary troubleshooting continue?

Rough 7

No happy ending yet, but a few less unknowns. Still won't start, I have new plugs, wires and an ebay trailing coil. I hear the fuel pump running, but haven't tested with a volt meter yet. Just ordered a new fuel filter, maybe it'll be something simple...

Looking at the fuel pump with a volt meter in the back. What wires in the rear am I testing and any specific voltage that I should be looking for?

Anything obvious that I might be missing?

Cheers.

Rough 7

Ok, after some testing I'm not seeing spark in my spark plugs and I am getting fuel forwards of the fuel filter... so thinking fuel isn't the issue.

Took the L1 plug out and didn't see any spark when turning the engine over. Not sure if it should be largely visible, but didn't see anything. Thoughts?

Thanks.

DC5Daniel

iTrader: (10)

Just to clarify, you did ground the spark plug in some way and/or use some form of spark tester, correct?

Rough 7

Yes, we grounded it and looked for a spark with no success. Not sure if this is the correct way to perform this, but don't have a spark tester to use.

satch

iTrader: (1)

The lead coil must have 12 volts w/key to on at the Black/Yellow wire. Does it? If not, check the EGI INJ fuse.

Rough 7

"The lead coil must have 12 volts w/key to on at the Black/Yellow wire. Does it? If not, check the EGI INJ fuse."

Yes it does, just checked.

So coil or connection from there to the spark plug?

satch

iTrader: (1)

You need to locate the Green check connector w/4 wires near the lead coil and check the Black/White wire for 12 volts w/key to on. It's powered by the EGI COMP fuse.

Rough 7

Yes, just checked that black and white wire as well and it does have 12V. Hopefully I successfully uploaded an image of the connector I checked, but was green, four wires and close to the lead coil.

Appreciate the tips btw.

satch

iTrader: (1)

Go over to the pressure sensor and check the Brown/White wire w/key to on as it should read 5 volts. If it doesn't have 5 volts, but more like 0 volts, then unplug the AFM and retry the voltage on the wire previously tested and if it registers 5 volts then the AFM is shorting out the ECU and thus preventing the car from starting.

Rough 7

Will do, stuck for the night, but will try or get to it tomorrow.

Cheers!

Rough 7

So, before diving into this too deep... please excuse my naivety, but where is the pressure sensor located and what's meant by AFM?

Thanks.

satch

iTrader: (1)

Use the Brown/White wire of the TPS instead of the pressure sensor. Air flow meter (AFM).

Rough 7

Getting 5V at the brown/white wire at the pressure sensor. So that's looking good so far.

What's throwing me off is that the car started about a week ago and drove all the way home (granted, a little rough). Is it possible that I simply didn't hook things up properly when swapping out new plugs and wires? Not exactly my first rodeo here, but maybe I'm missing something. Obviously I am!

Is there a way to check the coils themselves... although I doubt that's the issue. I have two sets (used) right here and have tried them both.

Thanks again for the help.

satch

iTrader: (1)

The coil needs to be bolted firmly to the fender for grounding purposes or it won't work.

A good way to check for spark is to pull the plug wires off of the coil bore and rest them against the bore and w/key to start you should see spark.

Also, the Green/Yellow wire at the lead coil is the trigger for the coil. Rotating the main pulley by hand (done by rotating the alternator pulley) should cause the voltage on the G/Y wire to alternate between 0 volts and 5 volts w/key to on (voltage value stays one number before briefly switching to the other value).

Rough 7

Cool, will take a second look and post the results later this evening. Thanks!

Rough 7

Looking at the picture, the green/white-ish wire is getting up to 0.4v and that's all. I think this is the one that should be going up to 5v as mentioned above. Maybe the issue? Otherwise everything seems to have power. The leads to the coils themselves shown in the picture get 13.5v along with all the rest of the wiring up to and around the coils. Unplugged the spark plug wires at the coil end and didn't see spark. Same on the spark plug side (double checked anyway). None of the plugs are getting any spark though... so I don't think it's a coil issue. Ecu not sending a strong enough signal maybe?

satch

iTrader: (1)

Are you speaking of the Green/Yellow wire in the same plug as the Black/Yellow wire? Again, it is supposed to have a voltage level which alternates between two values as the main pulley is rotated by hand w/key to on, as it goes from 0 volts to 5 volts briefly and then back to 0 volts thus you are looking for the change from 0 to 5 and then back to 0 again.

Rough 7

Yes, that's the wire. I was able to read up to 0.4v (alternating between 0.4 and 0) when turning the engine over using the starter. I wasn't able to get any reading other than zero when turning it by hand. Didn't alternate at all.