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Engine won't rev past 2,000 RPM - just cleaned engine bay


PhilbertZ

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Putting on my flame suit for this one....I just joined forum and seem to have done nothing but ask for lots of help (but have been successful in getting it from you guys, so I'm going to continue to press my luck!).

 

So....the car has been running fine since the new alternator a few weeks back.

 

However, I washed it a couple days ago and decided to use the generic orange and white can engine bay degreaser when I did this (from Kragen/Shucks/Checkers store). I checked the engine bay for inlets that the dereaser/water might get into but didn't see any obvious ones. With the OEM hood vents, it seemed like the engine bay was pretty robust as far as having liquids sprayed on it (degreaser and the water to rinse afterward). I sprayed the degreaser on, let it sit for 15 minutes, then rinses off, and ran the engine for 15+ minutes, just like the can said. Car seemed fine - parked it for 2 days.

 

THE BIG PROBLEM:

 

This morning, I drove it 10 miles or less to the train station for my commute. Noticed right away that it wouldn't rev past 2000-2200 RPMs - just cut out like a normal rev limiter would. This happened in all gears - if I downshifted, it would bog down to the 2000RPM limit - the only way I could get up to 45 MPH was to be in 5th gear - had to take surface streets instead of the freeway.

 

I had a few minutes at the station to check under the hood but found nothing out of the ordinary. Took off air filter housing and it looked dry and just fine.

 

I did some searching here on the forum when I got to work this morning but found nothing similar yet.

 

Has anyone had this happen and if so, what's the fix to get it running again please?

 

Thanks in advance!!

 

Phil

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Thanks Steve for the fast reply!

 

I'll check that out and give it a shot. I have been unsuccessful the past few minutes searching online for the location of the TPS but I have a 2 inch thick service manual at home for this model, so I'll consult that sucker before diving into the engine bay.

 

Will water likely ruin the TPS or just provide incorrect readings to the ECS until I "dry it out"? Is letting it sit for a day before drying it out going to be bad? And lastly, would it just dry on its own if left for a while (not trying to avoid doing this - just wondering since it's not a daily driver and I have a pretty busy week till the weekend.

 

Thanks again!

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TPS = Throttle Position Sensor. It's 99.9% of the time located on the throttle itself on cars.

 

You'll see it on the outside of the throttle, oposite side of the block. It'll be a little black box screwed into the throttle body with some wirse comming out of the top.

 

Take it off, let it air out, maybe blow some air on it and in the hole via a compressor. I've never had water damage my TPS for good, and it's had it's chance.

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The water completes a high impedance circuit and tells the ECU that the engine is under de-acceleration. In this mode the ECU shuts off the injectors at any rpms over 2800.

 

..would it just dry on its own if left for a while?

 

No. It will not dry out on its own. The entry point is so small that you will not get the exchange of air necessary for evaporation to occur. Also, water can enter the TPS connector through cracks where it has the same results.

TPS_thumb.jpg

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We'll see Gollum - still want to make some changes, mods, etc to my ride before going to a show - it's in need of some TLC on both the exterior and interior - some long term projects I want to gradually ramp up to ("Buy House with Garage, then start" is the plan).

 

BTW - for longer term...is there a sticky or thread you guys know of for getting the most out of a NA S130 (Exhaust, intake, plug wires, distributors, other "bolt ons")? The 132 HP is a little modest for a car this heavy, and as I replace/upgrade parts over time, I would like to choose the right ones to make up the best package in the long run.

 

Plus, the last long trip I took ended with a dead alternator in Benicia - that wasn't fun :) I want to make my car more reliable before trying something as far as Vacaville!

 

Which show is this BTW?

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Oh man, i wish you'd had my number, i'm in benicia nearly every night. I'm sure I could have helped you out in some way, even if it was just a casual drink to take the edge off the drama.

 

And my car looks like a POS and I'm going. These shows aren't as much of a car show as most, it's about just hanging out and meeting new people. Most of these norcal bunch are pretty easy going people.

 

As far as getting the most out of the L28E - Mr.Insane did a write up in the FAQ section on L series performance increases, but honesty he doesn't have much hands on experience (though I do appreciate the guy and enjoy talking with him) so it's not exactly biblical information. It's mostly just stuff he's got off of this site.

 

But that being said without getting into the head or adding cubic inches you probably won't see more than 175 wheel HP out of that motor. Though there's quite a bit you can do to make it more responsive and alive.

 

The sad part is that you're in CA which means smog, and one of the most infuencial mods you could make would be to go to a standalone ECU so you could run a MAF or MAP based system, which would meter air better and not choke the motor like the stock AFM. Most guys note a VERY noticable responce increase when switching to megasquirt.

 

There's the other obvious things you can do like a lighter flywheel, free flowing exhaust, etc. Though it's basically like tuning any other mild performance NA motor, the gains are small and don't tend to add up to a ton.

 

If smog laws wheren't in the way I'd say go with a standalone efi system, get a ITB setup, delete the cat and get a good header with a good size exhaust with a non baffled muffler. Then just work on messing with the ignition system from there.

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Thanks Gollum - I'll check out his post and bookmark it for the future when I can start doing these things.

 

I actually broke down in the morning so AAA came to the rescue and we found the ONE shop open there on a saturday - whew! We were going to leave the Friday night before - around midnight - but decided not to due to the lateness factor and we were tired...thank GOD for that in hindsight!

 

Cheers!

 

Phil

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Thanks everyone again for your help.

 

I limped home last night (worked great for the first few minutes till I got it on the freeway, then bogged down again). Got home very late last night so tonight is the night I'll dive in and "air it out".

 

I found the TPS and checked it at a high level - the boot is totally cracked and I can see the wires inside - no wonder water got in there!

 

I'll attack it tonight and get it dry. My other question is, can the boot be replaced, or should I just wrap with electrical tape for the future? I couldn't find the boot in my BlackDragon catalog - just the TPS part.

 

Cheers!

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I found the TPS and checked it at a high level - the boot is totally cracked and I can see the wires inside - no wonder water got in there!

 

I'll attack it tonight and get it dry. My other question is, can the boot be replaced, or should I just wrap with electrical tape for the future? I couldn't find the boot in my BlackDragon catalog - just the TPS part.

 

http://www.eagleday.com/ampconnectors.html

 

AMP-CON-BOOT $3.95

 

I have also seen a similar item on eBay in the past.

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So...last night I had some time and tackled this - damn it was easy.

 

Removed the TPS and the plug (with rotting electrical rubber boot) and sprayed them both out with canned air (that stuff is tricky - it sprays liquid if you tilt the can at the wrong angle!). Once I had the brunt of the liquid cleared out of both parts (there was a lot), I took my wife's hair dryer to them to thoroughly dry them both out. I then tore off the rotting boot and wrapped the plug with electrical tape to create a somewhat good seal. Pieced it all together, took it for a spin and WOW - the 6,000 RPMs are BACK baby!!

 

Spending some more time poking around the engine bay I noticed that pretty much every "boot" that surrounds a connector like the TPS or my fuel injectors is rotted and cracked through....think I'm going to have to place an order to one of those online places that sells replacements. I took general width measurements of each boot that I need - does anyone have advice on how to best apply new boots? Do I need to remove the wiring from each plug to make this happen or are there kits that you can "self seal" with heat shrinking or something similar?

 

Again - to all who chimed in here: a BIG THANK YOU - this forum rocks! :D

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  • 8 months later...
Guest awalburn

:cry:

I have the exact same problem with the engine not revving past 2000 rpms or so. The only addition in my case is that the problem seems to be activated by being in very slow or stop and start traffic. The car will stall, and when I restart the engine, the revving issue will appear. Could this still be caused by water in the TPS, and hopefully not something more serious? I can get some speed by upshifting so the low rpms are maintained. Thanks in advance.

 

Amanda

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http://www.eagleday.com/ampconnectors.html

 

AMP-CON-BOOT $3.95

 

I have also seen a similar item on eBay in the past.

 

Funny thing, went to our local nissan distributor this past weekend, and purchased the newer style connector as seen in that link, complete with new boot and pig tail wiring for 6.95 each. Big plus is being able to squeeze the bail wire and release the connector over the older style.

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I had the same problem. Those electrodes I think they are called, on the spark plug (the thing the wire snaps onto) are screwed on. Mine came out of the box and they were loose. I tightened them down but they sometimes come loose again and it creates the same problem but at 4000RPM. It will also happen if a spark plug has come loose too.

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  • 4 weeks later...

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