2G low oil pressure - too many variables

[Topdown]

I have searched and read post after post here, but I fear that there are too many variables with my car to get a general answer. I am new here, new to DSM's...so, hello!

so, 97 GS-T Spyder, completely stock.

I broke a timing belt, and have spent the summer pulling the head out and getting that rebuilt. That may be a project that seems small to most here, but It was more than I have ever done.

Well, the head went in fine, valves were bent. Got it all back together again and started it up again. I followed standard procedure, primed the oil by pulling engine fuse, etc. Much to my surprise it started right up, and immediately began spraying oil out of the turbo feed line. I replaced that with an aftermarket flexible steel braided line, and started her up again. Everything stayed together this time, but the idle was horrifying. Inspection revealed exhaust cam to be one tooth off. So, eight hours later that was fixed. Started up again, and sounded much better. My idle is still really rough, and I am missing every once and again. Not in any particular cylinder, and the consensus is a bad ignition coil.

So, because of the miss, the idle is rough. I, again, am assuming it's a coil, any other ideas would be appreciated.

Now on to the oil pressure. Everything is fine until the car warms up. Then, I get a flickering oil light which turns into a solid oil light...at idle. As soon as you step on the gas, it disappears until the next stop light. At the same time, the oil gauge is all over the place, up to normal on acceleration/cruising, and sinking at idle. The oil light comes on independent of the gauge. (to explain, the oil light comes on as soon as you take your foot off of the gas, and with the gauge still reading high/normal. The oil light goes away as soon as you step on the gas, with the gauge reading super low.)

I have seen people in response to posts like mine screaming 'crankwalk.' Yeah, I don't think so. None of the other symptoms are occurring, no problems related to clutch, etc.

I have seen people state that this problem is due to blown rings. Well, damn I hope not. I am not losing oil, I have no smoke, no oil smell in exhaust.

I did put in Mobil 1 synthetic, never had that before. Also the new braided turbo line would have less resistance to flow then the stock line.

Or, maybe it is the miss, which messes with the idle, and really does spin the oil pump less efficiently.

I apologize for the length, it is just that I have spent the last 2 hours reading posts like "my oil light is on...why?" and have seen the follow-ups trying to get all the info to fill in the story.

Regardless of the outcome here, I am hooked. I'll keep this one until I can get a GSX.
Any help is appreciated.

 

[DSM nOOb]

what weight oil are you running. Try maybe running like 10w-30 and see if that helps. Also how many miles are on the car.

 

[Topdown]

I don't recall the weight of the oil right now, but the block has 142,000 something on it. The head about 20.

 

[bomper04]

on the 6-bolt block, the oil pump and balance shafts have to be timed as well. there are notches on the front case to line up with the appropriate pulleys. i'm not too sure about the 7-bolt on the 2g's though. do you have access to alldata? or if you can find a thread on doing the t-belt on a 7 bolt.

 

[Topdown]

Yep, to my knowledge, timing marks all need to be aligned on a 7 bolt as well. It seems though, that the only purpose of this is for the balance shafts. A misaligned oil pump gear would give the engine a terrible shake, but shouldn't affect oil pressure.

Regardless, I am positive that the balance shafts are aligned. I say this because I put the timing belt on the first time without considering this, found out about it, took it off, and made sure of it the second time.

 

[Calan]

I think I would concentrate on that miss and horrible idle first. There could be something with the t-belt job that is causing both that and the oil pressure problem, or like you said...the idle could just be so bad that the pump isn't turning enough to keep pressure up.

I'd figure that out first, and then see what happens with the oil pressure...assuming you have enough oil pressure at idle that your motor isn't in danger of course.

Even under normal conditions, oil pressure in a 4g63 at idle may be only a few PSI above throwing a warning light.

 

[Defiant]

Start simple. Oil sender wire connection may be loose, or the sender itself may be dying.

 

[My1GLaser]

Like Defiant said the wire could be loose. Mine was and did the same thing, so I replaced the electrical connector.

Also, synthetic oil seems to be thinner than conventional oil. Although it might be the same viscosity, it just seems lighter and could cause lower oil pressure IMO. I ran Amsoil 10w30 on my first DSM, and it drained out like water when I did oil changes.

 

[Calan]

the oil light comes on as soon as you take your foot off of the gas, and with the gauge still reading high/normal. The oil light goes away as soon as you step on the gas, with the gauge reading super low

The warning light and gauge each have their own sending units. The warning light sender is simply a switch that closes to ground when pressure drops below it's threshold, and the guage is driven by a variable resistance that changes with pressure, so the guage will have a slower response. Since they both seem to be functioning as expected from your description, I think you may have a true oil pressure problem.

EDIT:

Ehhh... that ^^^ is on a 1G. I assume yours would be similar if not identical, but I'm not sure of that.

 

[Topdown]

Since the gauges are independent circuits, I am assuming that the oil pressure is low. I agree with the idea of 'fix the idle first.' My concern at this point is that it's my daily driver, and the soonest I can get coils in is the weekend. I just don't want to damage the engine in the meantime. The oil pressure is good and the light is off for 80% of my drivetime.

I do believe that the synthetic has less resistance to flow. What doesn't make sense to me is the fact that there was NO problem when the timing belt broke. It seems unlikely that the oil pump started failing this quickly, this soon after a major repair in another area.

So I guess at this point, I'll just drive it as little as possible, and get the idle taken care of this weekend, hopefully.

 

[Calan]

As another member recently pointed out in a similar thread, you could also have worn bearings (causing a drop in pressure), and the motor is about due to be freshened up.