Help Diagnose Temp Gauge Issue

[kimmerkaze]

Hey so...just finished doing the following:

- HG replacement
- Mess under intake cleanup (ran a bypass hose from head to tube instead of plugs)
- Ran PCV direct from VC to intake boot
- Ran ICV direct from VC to intake boot
- Deleted that thermoswitch valve along heater core inlet line (from head to heater core)
- Deleted charcoal canister (plugged TB port, vented line from tank)
- Replaced a bunch of other gaskets (oil pans, intake, exhaust, etc etc)


- Verified both coolant temp sensor and temp sender connectors hooked up correctly


Symptoms:

- Rough idle - a bit of stutter but it's fairly inconsistent
- Temp gauge does not move off of cold when car's running
- When IG is ON, but engine not running, temp gauge needle goes all the way max hot and stays there
- Did stomp test and only got 1263, purve valve, which is probably because I removed valve as part of charcoal canister delete
- Bleed I think is ok now - have hot air coming through cabin and lower rad hose gets warm

Possible Causes:

- I do need to replace fuel filter (car's been also sitting for 7-8 months now) so I'm hoping this is what's causing rough idle - btw injectors are 'new' bought the 4 pintle ones

- Temp sensors - coolant sensor and temp sender both don't seem to be working properly? I did replace both of these with brand new ones... Will try to check continuity tomorrow



That's all I've got right now. Really need to get this thing back on the road tomorrow or I'm SOL for work Monday.

Any help is much appreciated. I'm still searching online too and have found a couple of threads where people have same temp gauge symptoms but no true fix reported from what I can see.

Thanks in advance

[kimmerkaze]

Ok found 1 very possible lead that I will confirm tomorrow morning (too loud to start car right now haha):

*Rear temp sensor (sending to gauge) may be switched with oil filter housing sensor*

This makes sense since my gauge isn't working and my oil light is on.

Hopefully this fixes that issue and only thing left is some idle issues, which I'm hoping fuel filter will take care of.

[DesktopDave]

I had switched all three plugs on mine too - I had a dim oil pressure warning light, coolant temp as wrong, etc.  That temp sensor is a PITA to get at once the manifold is bolted back in...

I'd be tempted to replace that heater core bypass - it was a recall to deal with heater core failures from high pressure and temperatures.

I'd guess your trouble is the purge valve/charcoal canister.  The fuel tank needs to be vented to the atmosphere via that purge valve to function properly.  You might be starving the pump by applying a vacuum to the tank.   Also, in my neck of the woods your car would fail our annual emissions inspection.  That can isn't pretty, but it doesn't hurt performance in any way...and also keeps the car from smelling like raw fuel...

[kimmerkaze]

Thanks Dave.

Yeah so out of the 3 plugs, 2 are single contact and 1 is double. The double I got right, which is the coolant temp sender to DME (front location on cyl head). I actually ended up switching the single contacts (both are also black connector) the oil filter and temp gauge connectors so now lights gone but I want to go through bleed procedure once more to ensure everything's good with cooling.

I should've known better though I now recall I made a mental note of the wiring orientation when I pulled them. The oil filter and front DME temp sensor wiring branch out from same wire whereas the temp gauge connector is independent. For some reason the slack in wiring made more sense to switch oil filter and temp gauge connectors and they were both single contacts so that's where I made my mistake during re-assy.

I looked around a lot for bypass feedback from people and generally it seems like if you keep up your cooling system maintenance I doubt there will be an issue. Plus it's only the US cars that got that (how typical...haha).

As for charcoal canister situation, I'm kind of confused by your explanation but I think I should clarify/confirm. I plugged the throttle body port only. For the tank line that comes up against firewall and into charcoal canister I actually extended that line and looped it into my FR LH wheel well for venting so it's not plugged.

The canister I had is super super crusty and I'm sure it's doing nothing. As for emissions, I have a way of going around that up here

Plus, I've held onto the clamp for the canister because for a small project I'd like to fab up a catch can similar size to charcoal and put it down there where charcoal can used to be and route PCV through there. What do you think?

[kimmerkaze]

And yeah gauge temp sensor is a PITA. I think it's almost impossible if you keep the regular mess under intake but it's still doable once you delete all that stuff.

[kimmerkaze]

*Update*

Oil light gone, temp gauge now works

Cause: Switched around black 1 contact connectors.

Key point: The Y-split in wiring has 1 grey and 1 black connector. Grey goes to front coolant temp sensor for DME and black goes to oil filter housing

The one lone black connector goes to rear coolant temp sensor for temp gauge


*Idle is still a tad rough especially during cold. Changed fuel filter too. Going to ride it out for now and see what happens when I fill up next tank with gas that isn't 8 months old lol

[keflaman]

I've got my temporary replacement motor 3-pointed in the car and if I didn't label the connectors this info is going to come in handy!

[kimmerkaze]

*Update*

Drove the car around today. Noticed a few things:

1) Temp gauge needle begins to creep slightly over half point (like needle just moves past 1/2 mark) after I come off of highway and begin to city cruise

- I think I need to put back in my aux fan for A/C. I removed A/C condenser and aux fan last year but ever since I've had it out temp creeps a bit on very hot days in stop and go traffic

2) Still having a rough idle - sometimes random stalls when I come to a stop or clutch in

- I'm lost here. My only thinking is maybe the gas is no longer good. Full tank has been sitting with stabilizer from Oct '11 until now (~8 months). I think it would normally be ok if system was sealed but I removed vent line off of tank from canister so maybe fuel could've degraded faster? Not sure but if someone could help out here that'd be great

- ICV cleaned again seems no issues
- AFM very clean no sticking. Same with TB
- No O2 sensor code

- Only other thing I can think of is maybe my timing is off but I did mark everything pretty thoroughly / accurately when doing HG.


Anyway, will try to temporarily come up with something to hold aux fan back in w/o condenser and siphon out gas tonight too and replace.

[kimmerkaze]

Ok so quick update to close this thread out. Sorry for the long post(s) but I wanted to follow up in case anyone else has these same issues in the future:

1) Temp gauge creeping past half

- Solved by wiring back aux fan in and bypassing temp switch (new rad has a plug in it) so it triggers high speed
- Plan is to order lower temp rad sensor and wire all that back in. Possibly wire in separate manual toggle for when car's off for track

I used this diagram to help me troubleshoot:



- FYI, took me awhile to get this going because I kept playing around with the 3 connector plug on the RH side of rad. Everytime I jumped temp sensor I could hear K1 & K6 relays trigger.

- I then jumped bk/gr to bk/bn on temp switch to trigger hi speed and then checked continuity on RH fan switch connector but no juice. Didn't make sense to me so I dug around a bit on the LH side under the headlamp and found the same connector! Continuity check and it was getting juice so I guess I just forgot where I removed aux connector from last time.

- Plugged aux fan to LH bodyside connector, put some spade connectors on rad temp switch bk/gn to bk/bn and A/C switch worked fine. Fairly ghetto but for now it'll do just to get by for the next few weeks.


2) Rough idle

- Drained fuel last night and refilled. Hesitation is gone! Idle is still not perfect but definitely close to being stable. Will follow up with a timing check down the road because I may have been slightly off tightening down cam gears

- I definitely think this was due to me venting fuel tank line by removing charcoal canister early on in winter and leaving things vented for a few months. Even though I had stabilizer in the tank it didn't help. From what I understand system should be sealed during storage.


3) Supercharger like whine noise gone

- All day long Sat whenever engine was running whine noise would change with rpm. Sounded pretty much like a supercharger. Re-confirmed all belt tensions and listening to noise closer sounded like it was coming from timing cover. Dug around online and my best guess was to change out chain tensioner. I ordered a new one but didn't install because old one seemed ok.

- Pulled out old tensioner and it seemed to be extended all the way. Maybe it was getting stuck and the chain was rubbing hardcore on the RH guide that tensioner pushes up against? Not sure.

- Popped in new one (pre-compressed) and broke in the new tensioner. My god I'll never forget the sound that the chain made. Can't describe it but it was enough to stall my engine and even cranking after, the engine didn't want to run. I gave it some gas next start and kept revs around 3500 like one procedure said. After about 5-10 seconds you could hear the chain noise subside in intervals and then after about 10 seconds engine started purring.



So all in all pretty efficient weekend.