Fuel pump assembly project- double checking for ghosts
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Zen Vet Master Level VII
Joined: Mar 2016
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From: Southlake, TX
Fuel pump assembly project- double checking for ghosts
I’m going to pull my fuel pump assembly this weekend on my ’89 as the gauge on the dash is all wonky and I think it is the sending unit.
I’m just double checking my symptoms so I’m not chasing ghosts…
Upon starting the gauge will read full, regardless of the fuel level.
Over time it will S L O W L Y drop to a different reading, but clearly not accurate. The pump is fine and the car has plenty of pressure.
What I’m planning on doing is pulling the assembly out and cleaning the contacts around the float arm and sending unit. I’ll be careful around any coil wiring (cleaning with W40 and a Q-Tip, not sand paper) and freshen/sanding the contacts and making sure the float arm has free travel. The car sat of a long time before I bought it, so there may be some rust.
Sound OK or is there anything to run down first?
I’m just double checking my symptoms so I’m not chasing ghosts…
Upon starting the gauge will read full, regardless of the fuel level.
Over time it will S L O W L Y drop to a different reading, but clearly not accurate. The pump is fine and the car has plenty of pressure.
What I’m planning on doing is pulling the assembly out and cleaning the contacts around the float arm and sending unit. I’ll be careful around any coil wiring (cleaning with W40 and a Q-Tip, not sand paper) and freshen/sanding the contacts and making sure the float arm has free travel. The car sat of a long time before I bought it, so there may be some rust.
Sound OK or is there anything to run down first?
Thread Starter
Zen Vet Master Level VII
Joined: Mar 2016
Posts: 5,218
Likes: 1,174
From: Southlake, TX
Thread Starter
Zen Vet Master Level VII
Joined: Mar 2016
Posts: 5,218
Likes: 1,174
From: Southlake, TX
Roger that. I took it apart after work today. The disassembly was really straight forward with no issues.
The sending unit came apart easily and I was careful of the metal tabs. The was reasonably dirty so I cleaned it up with cotton and WD40 and light sanding of the contact point. Assembly was equally uneventful (How many times can you say that about a C4?)
I "bench tested" the new pump and the sending unit. The pump whirled on and the gauge showed on the dash accurate a empty, half and full.
The only thing that threw me a bit is that the dash gauge moved very slowly, but I guess that is to have a timed delay compensate for the "slosh" of the gas while driving. It moved slowly but it DID settle at the correct marks.
It took me 90 minutes but that is because I get distracted with side projects and beers.
TOTALLY worth the effort if your gauge is wonky.
The sending unit came apart easily and I was careful of the metal tabs. The was reasonably dirty so I cleaned it up with cotton and WD40 and light sanding of the contact point. Assembly was equally uneventful (How many times can you say that about a C4?)
I "bench tested" the new pump and the sending unit. The pump whirled on and the gauge showed on the dash accurate a empty, half and full.
The only thing that threw me a bit is that the dash gauge moved very slowly, but I guess that is to have a timed delay compensate for the "slosh" of the gas while driving. It moved slowly but it DID settle at the correct marks.
It took me 90 minutes but that is because I get distracted with side projects and beers.
TOTALLY worth the effort if your gauge is wonky.
Last edited by billschroeder5842; Jul 14, 2017 at 08:50 PM.
Thread Starter
Zen Vet Master Level VII
Joined: Mar 2016
Posts: 5,218
Likes: 1,174
From: Southlake, TX
*UPDATE*
I filled up this morning. The gauge showed one bar less than 1/4, so my guess was 16ish gallons. It took 15.8 to fill and the gauge read full up.
I drove 45 miles today for my commute and the gauge dropped two bars--- not stuck at full for a gazillion miles.
This was SO worth the effort.
I filled up this morning. The gauge showed one bar less than 1/4, so my guess was 16ish gallons. It took 15.8 to fill and the gauge read full up.
I drove 45 miles today for my commute and the gauge dropped two bars--- not stuck at full for a gazillion miles.
This was SO worth the effort.
