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Oil psi trouble. Help? by 86fiero3.4
Started on: 07-29-2013 09:21 AM
Replies: 14 (240 views)
Last post by: 86fiero3.4 on 07-30-2013 08:00 AM
86fiero3.4
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Report this Post07-29-2013 09:21 AM Click Here to See the Profile for 86fiero3.4Click Here to Email 86fiero3.4Send a Private Message to 86fiero3.4Edit/Delete MessageReply w/QuoteDirect Link to This Post
86 with a 3.4pr

The gauge pegged to the right at first.
I replaced the sending unit and now the gauge works.
But when running it stays left reading no psi and the light is on.
When reving the motor a little the needle bounces but still shows no psi.

What could it be and how should i go about fixing it?
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Fiero84Freak
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Report this Post07-29-2013 09:49 AM Click Here to See the Profile for Fiero84FreakClick Here to Email Fiero84FreakSend a Private Message to Fiero84FreakEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 86fiero3.4:
I replaced the sending unit and now the gauge works.


Did you use a thread sealer on the threads when you replaced it? You shouldn't. It can mess up how the sending unit works in relation to the gauge. It should seal fine anyway without thread sealer.
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86fiero3.4
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Report this Post07-29-2013 12:45 PM Click Here to See the Profile for 86fiero3.4Click Here to Email 86fiero3.4Send a Private Message to 86fiero3.4Edit/Delete MessageReply w/QuoteDirect Link to This Post
No i did not. And there are no leaks.
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Blacktree
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Report this Post07-29-2013 12:48 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
Your new sender is probably faulty, too. I once had to go through 3 new senders before finally getting one that worked properly.

That said, you might want to double-check using a mechanical gauge, just to be sure.
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Lou6t4gto
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Report this Post07-29-2013 06:45 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
A mechanical Gauge won't lie to you. put in a "T" and have the mechanical for backup.
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Marvin McInnis
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Report this Post07-29-2013 07:37 PM Click Here to See the Profile for Marvin McInnisClick Here to visit Marvin McInnis's HomePageSend a Private Message to Marvin McInnisEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Fiero84Freak:

Did you use a thread sealer on the threads when you replaced it? You shouldn't. It can mess up how the sending unit works in relation to the gauge. It should seal fine anyway without thread sealer.



Not quite true. All NPT threads need some kind of thread sealant to avoid leakage. The crest of the threads will not mate perfectly with the valleys, and the resulting gap can form a spiral leakage path.

The key is that you should not use thread sealing tape (e.g. Teflon tape) on threads that also form part of an electrical circuit; the tape may form an insulation barrier between the male and female threads. For these threads you need to use a liquid or paste thread sealant.
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86fiero3.4
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Report this Post07-29-2013 09:00 PM Click Here to See the Profile for 86fiero3.4Click Here to Email 86fiero3.4Send a Private Message to 86fiero3.4Edit/Delete MessageReply w/QuoteDirect Link to This Post
Dont need a lesson on sealing threads...
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Bloozberry
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Report this Post07-29-2013 09:19 PM Click Here to See the Profile for BloozberrySend a Private Message to BloozberryEdit/Delete MessageReply w/QuoteDirect Link to This Post
Is that all you did... replace the sender? Or is this result after some major engine work like a rebuild and/or oil pump replacement? If all you've done is replace the sender, then I'd suspect the sender or the wiring to be the cause. On the other hand if you're getting low oil pressure after other work it would help if you said so. For example the symptoms you're getting are also what happens when you forget to put in one of the little oil gallery plugs deep inside the engine during a rebuild.
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86fiero3.4
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Report this Post07-29-2013 09:39 PM Click Here to See the Profile for 86fiero3.4Click Here to Email 86fiero3.4Send a Private Message to 86fiero3.4Edit/Delete MessageReply w/QuoteDirect Link to This Post
Nothing was removed from the engine.
I got it as a long block.
Pulled the crank, rods, and pistons.
Had it honed and washed. Put new rings and bearings in it along with an oil pump.
The pump is working. If i use a high speed drill on the shaft it pumps oil.
It seems to be getting oil through the motor but the gauge reads 0.
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Marvin McInnis
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Report this Post07-29-2013 10:02 PM Click Here to See the Profile for Marvin McInnisClick Here to visit Marvin McInnis's HomePageSend a Private Message to Marvin McInnisEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 86fiero3.4:

Dont need a lesson on sealing threads...



OK.
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Bloozberry
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Report this Post07-29-2013 10:05 PM Click Here to See the Profile for BloozberrySend a Private Message to BloozberryEdit/Delete MessageReply w/QuoteDirect Link to This Post
I don't mean to belabor the point, but your post is a little confusing when you say nothing was removed from the engine, yet the crank, rods, and pistons were pulled. I assume if you took out the pistons, you also had the heads removed since compressing the piston rings to re-install the pistons from the bottom isn't easy. Assuming that when you say you had it "washed", you mean it was professionally hot tanked and not just pressure washed, the machine shop would have removed any oil gallery plugs to help flush the internal oil passages. (I can't say for sure if there are any in the 3.4, but I would assume there are.) In case you're not familiar with what I'm talking about, here is a 2.8 showing where they would go... they're very easy to overlook when rebuilding. I overlooked one once... that's why I know what the symptoms are.



Hopefully it's just the gauge or the sender.

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Blacktree
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Report this Post07-30-2013 12:43 AM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
Just FYI, oil pressure senders usually come with thread sealer pre-applied. So the whole thread sealant debate, regarding the oil pressure sender, is basically moot.

Let's move on, shall we?
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86fiero3.4
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Report this Post07-30-2013 07:10 AM Click Here to See the Profile for 86fiero3.4Click Here to Email 86fiero3.4Send a Private Message to 86fiero3.4Edit/Delete MessageReply w/QuoteDirect Link to This Post
Bloozberry. I see what you mean. It was poor choice of words. But the plugs are there as far as i can remember.
Sorry about the confusion. And yes. I hope it is just the sender.
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olejoedad
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Report this Post07-30-2013 07:27 AM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 86fiero3.4:

Dont need a lesson on sealing threads...


Wasnt correcting you, he was referring to Fiero84Freaks erroneous statement.

Misinformation must be stamped out or it lives forever on the web. Anybody else have Lotus designed suspension on their Fiero?
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86fiero3.4
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Report this Post07-30-2013 08:00 AM Click Here to See the Profile for 86fiero3.4Click Here to Email 86fiero3.4Send a Private Message to 86fiero3.4Edit/Delete MessageReply w/QuoteDirect Link to This Post
Either way. And dont thread hop and ask your own questions in mine. Start your own thread. Thanks.
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