Swordpork's Red Pig

[Zed.]

Oct 15, 2021 21:04:02 GMT swordspork said:

Does anyone know about the map query? - Just curious as I know the vac line is supplied with the kit but it's not been used by the chap that set it up.

Ask the 'tuner? they've either a reason or forgotten...

Rich.

[swordspork]

Oct 15, 2021 21:36:03 GMT atlex said:

How is the tune setup ?

Thanks for the suggestions. I've been in touch with the tuner to understand how the ECU and tune are set up.

It was explained that the tune uses Alpha N (TPS) and the iat. In an n/a setup the map would be atmospheric at open throttle and negative (vacuum) at closed throttle. This is the reason for the alpha N mapping. However, forced induction would use MAP based fuelling.

I'm paraphrasing but that is the explanation.

Can someone explain for the layman what Alpha n is?

[atlex]

I know what it is, it's more common on ITB setups where the MAP signal isn't accurate/meaningful enough. I've got this setup on my ITB car.

Rare to see on a regular manifold setup, but it should work fine. :-)

Plenty of non-FI'd cars run MAP setups, btw. Almost every fuel injected corolla in the 90s ran them. My Carib runs with this also.

It's more specialist to setup Alpha-N than MAP.

[swordspork]

Oct 16, 2021 17:54:43 GMT atlex said:

I know what it is, it's more common on ITB setups where the MAP signal isn't accurate/meaningful enough. I've got this setup on my ITB car.

Rare to see on a regular manifold setup, but it should work fine. :-)

Plenty of non-FI'd cars run MAP setups, btw. Almost every fuel injected corolla in the 90s ran them. My Carib runs with this also.

It's more specialist to setup Alpha-N than MAP.

Ahh great that's good to know. I did a bit of reading and initially got the impression Alpha-N was used solely on ITB setups but it can be used on N/A.

I've read a few things that suggests hot cams can mean map readings at closed and low throttle isn't so reliable hence using Alpha-N instead.

For anyone interested the information mcgnms post on the below link explained theory compared to MAP and MAF.

www.m5board.com/threads/alpha-n-explained.531905/

[swordspork]

Just went out to get some petrol and the drive was interesting.... The idle wasn't great and it actually stalled a few times.

The tuner did say when I picked up the car that the idle valve was bad. I've been in touch and he's advised that once I change the idle valve he can send me the closed loop idle map.

Looks like I'm going to have to get the laptop out.

Danger to manifold....

[swordspork]

I've been reading up on the idle control system. The two main components are the idle air control valve (on the inlet manifold) and idle speed control valve (on the throttle body).

The tuner seems to think the issue was with the idle air control valve. I've removed this and tested as directed in rod's guide (cool valve in freezer and heat to see if there is movement of the internal shaft). The attached images show that upon heating the shaft moved away from the coolant connectors.

Does this mean that my issue is more likely with the idle speed control valve on the throttle body? I noticed that the issue is much more prevalent when the car is warm...

Warm



Cold

[swordspork]

I've spent much time in the last couple of days reading a lexicon of information on idle control and set up.

I've also partially disassembled the idle system on the car in an attempt to find fault.

In short I could find no clear issue with the idle air valve or the idle speed control valve. See image of a surprisingly in spec resistance value...

Bamboozled by technical jargon and having reached my DIY troubleshooting limit I was reluctant to go rogue and tweak settings and values that I wasn't too sure on.

Enter Dai from Valley5s. This man is a true fountain of knowledge on tuning. Specifically, in my case he was able to transform a really quite dodgey idle map (manual mode, with no open or closed loop control) to a very OEM feeling Idle and cold start. I would thoroughly recommend his services to anyone.

To give the original tuner the benefit of the doubt it does appear that the idle valve could be a bit sticky but this could ease up with use and shouldn't have hindered set up that much.

The general consensus I got was that many tuners can Dyno tune a car and get power out of it - some of the other aspects of mapping can be neglected or at least appear be an after thought....

I plan to drive the car more, fit a wideband and work with Dai to fine tune the map.

[lowender]

Oct 28, 2021 19:21:55 GMT swordspork said:

Enter Dai from Valley5s. 

Dai sorted out my idle issues a couple of years ago (MS2), and did some tweaks to the map whilst I drove the car. Highly recommended.

[atlex]

Anther Nod for Dai here. Glad he's still providing this service.

[swordspork]

Update time!!!!

I'd love to say that things have gone smoothly since driving and working with the car in its latest iteration but that would be a lie. 

Instead I have had to rectify quite a few issues. 

1. Harmonic Balancer on rebuilt engine was canoed (entire bottom end was bought for £20 of the bay) 

2. Original map had really bad cold start and idle behaviour. 

Number 1 was diagnosed really easily using the dipstick down number 1 spark plug method to find that the original 'notch' did not line up with the 'T' on the backplate. My theory is the balancer had slipped at some point in it's 30+ year life sure I could have re-marked tdc but I want to do things properly and ensure the balancer is working as intended. 

I ordered a new harmonic balancer, crank bolt, pulley bolts and boss, torqued everything to max spec with bleu loctite. All seems good now. 

Number 2 required a little more work as I went back to square one as far as the map goes, I fitted a new idle valve, plumbed in a MAP line (no more Alpha-N) and then wired up an AEM wideband. Removing the narrowband sensor was an absolute pig as I have an aftermarket hks manifold. I used a combination of swearing, brute force and luck to remove it. 

Myself and Dai then worked on road tuning the car starting with a ME base map and using the wideband to monitor AFRs. 

There is still more to do and Ideally I'd like to get the car on the dyno again soon to do final tweaks. 

The car now starts and drives fairly reliably - I wouldn't say it was exactly OEM as the fast road cams don't like to idle at the 900 rpm that the originals did therefore Idle is just over 1000 rpm to smooth things out. 

As far as learning goes if I was to go back and do things again I would probably do much more myself and only rely on trusted sources for help and advice. 

I will update with pictures soon....

[lowender]

I have the same setup on mine, MAP and IAT but with a MS2, it also idles at 1000rpm. It's been totally reliable, I haven't touched anything since Dai did some road tuning 3 years ago.

[swordspork]

After some discussion on another thread about oil filters I changed the filter I had on the car.

It was a mahle oc195 made in china. Although it's not clear to me yet whether these are legitimate made under licence or fakes they don't look to be of the same quality as European made filters bearing the same name.

I've found that there are a few Japanese made alternatives to look at for better quality filters and I'll try these out on my next oil change.

I'd steer clear of mahle if they are outsourcing manufacturing to China. Gsf sell Mann filters that I'm using right now and they are well priced and German made.

[swordspork]

Continued to drive the car with the wideband and autotune doing their thing. AFRs seem to be varying less. I try to hold the engine at a particular load to give the ECU time to do whatever.

Still not sure about this rebuilt engine. Going to keep driving it, if it drops it's shopping in a big way I'll 1.8 swap it and be done with it.

Bedford in February sounds tempting...

[swordspork]

To build on a post in another thread relating to oil filters. I had been in search of some decent Japanese made filters, after atlex tipped me off to some questionable Chinese mahle filters in circulation. I swiftly swapped this for a Mann filter.

I then found that it is possible to use a Mazda RX8 filter on the mx5. I'm not 100% on this but I think the model number below is for a revised version that was used by Mazda on a special edition RX8.

The filter is about 60% taller than oe spec Mann filter but uses the same thread so fits without issue.

I also changed to a fully synthetic millers oil, because I abuse the car when I drive it.

[howardb66]

Good one on the oil filter, I’ve always thought the std filter was too small.👍🏻