After market MAP sensors

[Vrv8hz]

I am having some trouble finding a replacement 3 bar map sensor. I am running a couple of cheap ebay delco style 3 bar map sensors that I purchased years ago on 2 of my cars, and they have been fine surprisingly. I originally started off buying a more expensive LS style unit that went bad in under a month, so I thought what the hell I'll give the cheap ones a try.

I recently bought 3 cheap ebay maps for projects that I'm currently working on and when they arrived they were completely useless. 3 different suppliers (maybe same production) and when bench tested they had no response to positive pressure.

So then I ordered 2x Genuine (listed) 3 bar Bosch maps from EFI Solutions. When they arrived I tested in car and the running conditions were awful. When bench tested the sensors would only output voltage to around 120kpa above atmosphere. Max signal voltage for one sensor was 3.7v and the other was 3.8v. Advertised voltage at 300kpa (approx 200kap above atmosphere) was 4.65v.

Am I missing something here? Or are these sensors bad?

I'm no engineer but shouldn't the tolerance be a lot better than what I am seeing?

Also, does anyone have a recommendation for a supplier for a good quality 3 bar MAP sensor?

[Charlescrown]

Sure your pressure gauge is accurate?

[Vrv8hz]

I've tried 2 gauges, same result. Whether the sensor stops at 3.8v at 220kpa or 300kpa, it's still not reading to range.

[Charlescrown]

Poor construction is the cause of many after market component failures. The big problem is OE parts are drying up for the older Delco system. AFI did carry OE parts but their now been sold so I don't know what the new company policy is.

[BennVenn]

I had the same issue, Could not get a turbo tune right, one day lean, one day rich. Ended up using one of these: https://www.ebay.com.au/itm/225873713488

If you put it in your manifold it doubles as a IAT otherwise you can remote mount it with a little bracket. This particular model is a 2.5bar Bosch clone

The formula if you're writing your own code: KPA =(54.11764706 * (ADC/1024*5) ) - 1.647058824

I pre-computed a table and use that

[delcowizzid]

The last good gm style 3 bar I bought was an autogauge or autometer boost gauge sender replacement

[antus]

I cant give you a known good seller but if I were you I'd ask EFI Solutions about that one and return it, and try other brandname sellers who have a reputation for quality. Haltech have one, so do link and a few other webstores. It can be an idea to tell them your story and ask them if they have confidence in the ones they have now, buy from a shop that does in the hope they have tested or know they have other customers using them or maybe some shop would be prepared to test one if they dont know and understand the problem.

[vlad01]

The only suggestion I have is to find another OEM GM electrically compatible MAP and buy it via one of the GM factory outlets online, like NewGMparts for eg, and see if you can get an ACDelco branded one if they have the option. I am finding Delphi stuff junk these days, and the ACDelco stuff made in Mexico still are the same 90s quality today. There is usually a huge price difference from Delphi and ACDelco from GM, even though they are being both sold from GM and under the same part number. Something there is even 3 options, China Delphi, USA ACDelco and Mexico ACDelco, the Mexican one being the most expensive, but all of those semiconductor devices, especially Honeywell devices are top notch manufacturing in Mexico, where the US is ok, but the US lost it's semiconductor edge in the 80s, where Chinese is the budget option and built to price and not to consistency.

Summit racing are great for the brand options for the same part, I always try to get the ACDelco stuff even if it's $$$, when a part lasting 15 year vs 15 weeks is double the price, I'll pay that!

[Vrv8hz]

I was playing around this arvo and pulled the map off the 1kd Hiace. Had a quick look at it on the bench and looks like might be close to 3 bar, maybe 3.5ish. If I order another one of these where do I adjust the values in 12p?Probably a rookie question, but I can't say I have had to look into it before.

[vlad01]

As far as I know, 1,2 and 3 bar are the only supported. I don't think there is a way to get in between values. I think I once looked into using 2.5 bar GM type for the same reason, one of the few genuine new MAPs that you could get at the time, and I recall it wasn't feasible, but maybe there is a way to work around that I am not aware of?

Never ended up going the boosted route in the end due to foreseeable reliability issues which many included availability of quality parts.